Organic electroluminescent apparatus

ABSTRACT

The present invention relates to an organic electroluminescent device comprising a mixture comprising an electron-transporting host material and a hole-transporting host material, and to a formulation comprising a mixture of the host materials and to a mixture comprising the host materials. The electron-transporting host material corresponds to a compound of the formula (1) from the class of compounds containing a pyridine, pyrimidine or triazine unit substituted by a dibenzofuran or dibenzothiophene.

The present invention relates to an organic electroluminescent device comprising a mixture comprising an electron-transporting host material and a hole-transporting host material, and to a formulation comprising a mixture of the host materials and to a mixture comprising the host materials. The electron-transporting host material corresponds to a compound of the formula (1) from the class of compounds containing a pyridine, pyrimidine or triazine unit substituted by a dibenzofuran or dibenzothiophene.

The structure of organic electroluminescent devices (e.g. OLEDs—organic light-emitting diodes or OLECs—organic light-emitting electrochemical cells) in which organic semiconductors are used as functional materials has long been known. Emitting materials used here, aside from fluorescent emitters, are increasingly organometallic complexes which exhibit phosphorescence rather than fluorescence. For quantum-mechanical reasons, up to a fourfold increase in energy efficiency and power efficiency is possible using organometallic compounds as phosphorescent emitters. In general terms, however, there is still a need for improvement in OLEDs, especially also in OLEDs which exhibit triplet emission (phosphorescence), for example with regard to efficiency, operating voltage and lifetime.

The properties of organic electroluminescent devices are not only determined by the emitters used. Also of particular significance here are especially the other materials used, such as host and matrix materials, hole blocker materials, electron transport materials, hole transport materials and electron or exciton blocker materials, and among these especially the host or matrix materials. Improvements to these materials can lead to distinct improvements to electroluminescent devices.

Host materials for use in organic electronic devices are well known to the person skilled in the art. The term “matrix material” is also frequently used in the prior art when what is meant is a host material for phosphorescent emitters. This use of the term is also applicable to the present invention. In the meantime, a multitude of host materials has been developed both for fluorescent and for phosphorescent electronic devices.

A further means of improving the performance data of electronic devices, especially of organic electroluminescent devices, is to use combinations of two or more materials, especially host materials or matrix materials.

U.S. Pat. No. 6,392,250 B1 discloses the use of a mixture consisting of an electron transport material, a hole transport material and a fluorescent emitter in the emission layer of an OLED. With the aid of this mixture, it was possible to improve the lifetime of the OLED compared to the prior art.

U.S. Pat. No. 6,803,720 B1 discloses the use of a mixture comprising a phosphorescent emitter and a hole transport material and an electron transport material in the emission layer of an OLED. Both the hole transport material and the electron transport material are small organic molecules.

WO2011088877 describes specific heterocyclic compounds that can be used in an organic light-emitting device as light-emitting compound, or as host material or hole-transporting material.

According to WO2015156587, specific carbazole derivatives can be used in a mixture with biscarbazoles as host materials.

According to WO2015169412, it is possible to use triazine-dibenzofuran-carbazole derivatives and triazine-dibenzothiophene-carbazole derivatives, for example, in a light-emitting layer as host material.

U.S. Pat. No. 9,771,373 describes specific carbazole derivatives as host material for a light-emitting layer of an electroluminescent device that can be used together with a further host material.

KR20160046077 describes specific triazine-dibenzofuran-carbazole and triazine-dibenzothiophene-carbazole derivatives in a light-emitting layer together with a further host material and a specific emitter. The carbazole here is bonded to the dibenzofuran or dibenzothiophene unit via the nitrogen atom.

WO2016015810 describes triazine-dibenzofuran-carbazole and triazine-dibenzothiophene-carbazole compounds, wherein the triazine substituent is bonded directly or via a linker in the 1 position of the dibenzofuran/dibenzothiophene, and wherein the carbazole substituent is bonded via its nitrogen atom in 8 position of the dibenzofuran/dibenzothiophene. The compounds described may be used in a mixture with a further matrix material. KR2018010149 describes similar compounds. WO2018174678 and WO2018174679 disclose devices containing, in an organic layer, a mixture of carbazole-dibenzofuran derivatives with biscarbazoles, wherein the linkage of the carbazole unit via the nitrogen atom to the dibenzofuran skeleton is possible at any position in the dibenzofuran.

KR20170113318 describes specific heterocyclic compounds that can be used as host material in a light-emitting layer of an organic light-emitting device.

KR20170113320 describes specific dibenzofuran derivatives that can be used as host material in a light-emitting layer of an organic light-emitting device.

CN107973786 describes triazine-dibenzofuran-carbazole and triazine-dibenzothiophene-carbazole compounds. The triazine substituent is bonded directly or via a linker in the 1 position of the dibenzofuran/dibenzothiophene. The carbazole derivative is bonded directly via the nitrogen atom or via a linker in the 6 position of the dibenzofuran/dibenzothiophene. It is further reported that these materials can be mixed with a biscarbazole H2 in a ratio of 10:90 to 90:10.

US20190006590 describes an electronic device comprising a specific sequence of two emitting layers, where each emitting layer contains two host materials. The first emitting layer comprises host 1-1 and host 1-2. The second emitting layer comprises host 2-1 and host 2-2, where host 1-2 and host 2-1 are the same material. Claims 7 and 8 describe specific biscarbazoles as host material 1-2. Claims 9 and 10 describe specific triazine derivatives as host material 2-2.

US2019047991 describes doubly substituted triazine-dibenzofuran derivatives and the use thereof as organic material in an organic light-emitting device.

WO19031679 describes organic light-emitting devices containing, in the emitting layer, a first host material comprising doubly substituted triazine-dibenzofuran derivative and a second host material.

WO19007866 describes compositions comprising an electron-transporting host and a hole-transporting host, where the hole-transporting host is a biscarbazole.

WO2020022860 describes organic light-emitting devices containing, in the emitting layer, a deuterated triazine derivative and a biscarbazole derivative.

However, there is still need for improvement in the case of use of these materials or in the case of use of mixtures of the materials, especially in relation to efficiency, operating voltage and/or lifetime of the organic electroluminescent device.

The problem addressed by the present invention is therefore that of providing a combination of host materials which are suitable for use in an organic electroluminescent device, especially in a fluorescent or phosphorescent OLED, and lead to good device properties, especially with regard to an improved lifetime, and that of providing the corresponding electroluminescent device.

It has now been found that this problem is solved, and the disadvantages from the prior art are eliminated, by the combination of at least one compound of the formula (1) as first host material and at least one hole-transporting compound of the formula (2) as second host material in a light-emitting layer of an organic electroluminescent device. The use of such a material combination for production of the light-emitting layer in an organic electroluminescent device leads to very good properties of these devices, especially with regard to lifetime, especially with equal or improved efficiency and/or operating voltage. The advantages are especially also manifested in the presence of a light-emitting component in the emission layer, especially in the case of combination with emitters of the formula (III), at concentrations between 2% and 15% by weight.

The present invention therefore first provides an organic electroluminescent device comprising an anode, a cathode and at least one organic layer, containing at least one light-emitting layer, wherein the at least one light-emitting layer contains at least one compound of the formula (1) as host material 1 and at least one compound of the formula (2) as host material 2

where the symbols and indices used are as follows:

-   X is the same or different at each instance and is CR⁰ or N, where     at least one symbol X is N; -   X₁ is the same or different at each instance and is CH, CR or N,     where not more than 3 symbols X₁ can be N; -   X₂ is the same or different at each instance and is CH, CR¹ or N,     where not more than 2 symbols X₂ can be N; -   Y is the same or different at each instance and is selected from O     or S; -   L and L₁ are the same or different at each instance and are a single     bond or an aromatic or heteroaromatic ring system having 5 to 30     aromatic ring atoms; -   R⁰ at each instance is independently H, D or an unsubstituted or     partly or fully deuterated aromatic ring system having 6 to 18     carbon atoms; -   R and R# are the same or different at each instance and are selected     from the group consisting of D, F, Cl, Br, I, CN, NO₂, C(═O)R²,     P(═O)(Ar₁)₂, P(Ar₁)₂, B(Ar₁)₂, Si(Ar₁)₃, Si(R²)₃, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20     carbon atoms or an alkenyl group having 2 to 20 carbon atoms, each     of which may be substituted by one or more R² radicals, where one or     more nonadjacent CH₂ groups may be replaced by R²C═CR², Si(R²)₂,     C═O, C═S, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where     one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or     NO₂, an aromatic or heteroaromatic ring system which has 5 to 40     aromatic ring atoms and may be substituted in each case by one or     more R² radicals, an aryloxy or heteroaryloxy group which has 5 to     40 aromatic ring atoms and may be substituted by one or more R²     radicals, or an aralkyl or heteroaralkyl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R²     radicals; at the same time, it is possible for two substituents R     bonded to the same carbon atom or to adjacent carbon atoms or for     one substituent R together with Ar₃ to form a monocyclic or     polycyclic, aliphatic, aromatic or heteroaromatic ring system which     may be substituted by one or more R² radicals; -   R¹ is the same or different at each instance and is selected from     the group consisting of CN, a straight-chain alkyl, alkoxy or     thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic     alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an     aromatic or heteroaromatic ring system having 5 to 40 aromatic ring     atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic     ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40     aromatic ring atoms; at the same time, it is possible for two     substituents R¹ bonded to the same carbon atom or to adjacent carbon     atoms to form a monocyclic or polycyclic, aliphatic, aromatic or     heteroaromatic ring system that may be substituted by one or more R²     radicals; -   R² is the same or different at each instance and is selected from     the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar₁)₂, NH₂,     N(R³)₂, C(═O)Ar₁, C(═O)H, C(═O)R³, P(═O)(Ar₁)₂, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40     carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon     atoms, each of which may be substituted by one or more R³ radicals,     where one or more nonadjacent CH₂ groups may be replaced by HC═CH,     R³C═CR³, C≡C, Si(R³)₂, Ge(R³)₂, Sn(R³)₂, C═O, C═S, C═Se, C═NR³,     P(═O)(R³), SO, SO₂, NH, NR³, O, S, CONH or CONR³ and where one or     more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂,     an aromatic or heteroaromatic ring system which has 5 to 60 aromatic     ring atoms and may be substituted in each case by one or more R³     radicals, an aryloxy or heteroaryloxy group which has 5 to 60     aromatic ring atoms and may be substituted by one or more R³     radicals, or a combination of these systems; where it is optionally     possible for two or more adjacent substituents R² to form a     monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring     system which may be substituted by one or more R³ radicals; -   R³ is the same or different at each instance and is selected from     the group consisting of H, D, F, CN, an aliphatic hydrocarbyl     radical having 1 to 20 carbon atoms, or an aromatic or     heteroaromatic ring system having 5 to 30 aromatic ring atoms in     which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I     or CN and which may be substituted by one or more alkyl groups each     having 1 to 4 carbon atoms; at the same time, it is possible for two     or more adjacent R³ substituents together to form a mono- or     polycyclic, aliphatic ring system; -   Ar₁ is the same or different at each instance and is an aromatic or     heteroaromatic ring system which has 5 to 30 aromatic ring atoms and     may be substituted by one or more nonaromatic R³ radicals; at the     same time, two Ar₁ radicals bonded to the same nitrogen atom,     phosphorus atom or boron atom may also be bridged to one another by     a single bond or a bridge selected from N(R³), C(R³)₂, O or S; -   Ar₂ at each instance is independently an aryl or heteroaryl group     which has 5 to 40 aromatic ring atoms and may be substituted by one     or more R² radicals; -   Ar₃ at each instance is independently an aromatic ring system having     6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5     to 40 aromatic ring atoms, which may be substituted by one or more     R² radicals; -   A at each instance is independently a group of the formula (3) or     (4),

-   Ar at each instance is in each case independently an aryl group     which has 6 to 40 aromatic ring atoms and may be substituted by one     or more R# radicals, or a heteroaryl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R#     radicals; -   * indicates the binding site to the formula (2); -   a, b, c at each instance are each independently 0 or 1, where the     sum total of the indices at each instance a+b+c is 1; -   o is 1, 2, 3 or 4; -   n, m and p at each instance are independently 1, 2 or 3; and -   q, r, s, t at each instance are each independently 0 or 1.

The invention further provides a process for producing the organic electroluminescent devices and mixtures comprising at least one compound of the formula (1) and at least one compound of the formula (2), specific material combinations and formulations that contain such mixtures or material combinations. The corresponding preferred embodiments as described hereinafter likewise form part of the subject-matter of the present invention. The surprising and advantageous effects are achieved through specific selection of the compounds of the formula (1) and the compounds of the formula (2).

The organic electroluminescent device of the invention is, for example, an organic light-emitting transistor (OLET), an organic field quench device (OFQD), an organic light-emitting electrochemical cell (OLEC, LEC, LEEC), an organic laser diode (0-laser) or an organic light-emitting diode (OLED). The organic electroluminescent device of the invention is especially an organic light-emitting diode or an organic light-emitting electrochemical cell. The device of the invention is more preferably an OLED.

The organic layer of the device of the invention that contains the light-emitting layer containing the material combination of at least one compound of the formula (1) and at least one compound of the formula (2), as described above or described hereinafter, preferably comprises, in addition to this light-emitting layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), an electron injection layer (EIL) and/or a hole blocker layer (HBL). It is also possible for the device of the invention to include multiple layers from this group selected from EML, HIL, HTL, ETL, EIL and HBL.

However, the device may also comprise inorganic materials or else layers formed entirely from inorganic materials.

It is preferable that the light-emitting layer containing at least one compound of the formula (1) and at least one compound of the formula (2) is a phosphorescent layer which is characterized in that it comprises, in addition to the host material combination of the compounds of the formula (1) and formula (2), as described above, at least one phosphorescent emitter. A suitable selection of emitters and preferred emitters is described hereinafter.

An aryl group in the context of this invention contains 6 to 40 aromatic ring atoms, preferably carbon atoms. A heteroaryl group in the context of this invention contains 5 to 40 aromatic ring atoms, where the ring atoms include carbon atoms and at least one heteroatom, with the proviso that the sum total of carbon atoms and heteroatoms adds up to at least 5. The heteroatoms are preferably selected from N, O and/or S. An aryl group or heteroaryl group is understood here to mean either a simple aromatic cycle, i.e. phenyl, derived from benzene, or a simple heteroaromatic cycle, for example derived from pyridine, pyrimidine or thiophene, or a fused aryl or heteroaryl group, for example derived from naphthalene, anthracene, phenanthrene, quinoline or isoquinoline. An aryl group having 6 to 18 carbon atoms is therefore preferably phenyl, naphthyl, phenanthryl or triphenylenyl, with no restriction in the attachment of the aryl group as substituent. The aryl or heteroaryl group in the context of this invention may bear one or more R radicals, where the substituent R is described below.

An aromatic ring system in the context of this invention contains 6 to 40 carbon atoms in the ring system. The aromatic ring system also includes aryl groups as described above.

An aromatic ring system having 6 to 18 carbon atoms is preferably selected from phenyl, fully deuterated phenyl, biphenyl, naphthyl, phenanthryl and triphenylenyl.

A heteroaromatic ring system in the context of this invention contains 5 to 40 ring atoms and at least one heteroatom. A preferred heteroaromatic ring system has 10 to 40 ring atoms and at least one heteroatom. The heteroaromatic ring system also includes heteroaryl groups as described above. The heteroatoms in the heteroaromatic ring system are preferably selected from N, O and/or S.

An aromatic or heteroaromatic ring system in the context of this invention is understood to mean a system which does not necessarily contain only aryl or heteroaryl groups, but in which it is also possible for a plurality of aryl or heteroaryl groups to be interrupted by a nonaromatic unit (preferably less than 10% of the atoms other than H), for example a carbon, nitrogen or oxygen atom or a carbonyl group. For example, systems such as 9,9′-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ethers, stilbene, etc. shall thus also be regarded as aromatic or heteroaromatic ring systems in the context of this invention, and likewise systems in which two or more aryl groups are interrupted, for example, by a linear or cyclic alkyl group or by a silyl group. In addition, systems in which two or more aryl or heteroaryl groups are bonded directly to one another, for example biphenyl, terphenyl, quaterphenyl or bipyridine, are likewise encompassed by the definition of the aromatic or heteroaromatic ring system.

An aromatic or heteroaromatic ring system which has 5-40 aromatic ring atoms and may be joined to the aromatic or heteroaromatic system via any desired positions is understood to mean, for example, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, benzofluoranthene, naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-monobenzoindenofluorene, cis- or trans-dibenzoindenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole.

The abbreviation Ar₁ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more nonaromatic R³ radicals; at the same time, two Ar radicals bonded to the same nitrogen atom, phosphorus atom or boron atom may also be bridged to one another by a single bond or a bridge selected from N(R³), C(R³)₂, O or S, where the R³ radical or the substituents R³ has/have a definition as described above or hereinafter. Preferably, Ar is an aryl group having 6 to 40 aromatic ring atoms as described above. Most preferably, Ar is phenyl which may be substituted by one or more nonaromatic R³ radicals. Ar is preferably unsubstituted.

The abbreviation Ar₂ at each instance is independently an aryl or heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals, where the R² radical or the substituents R² has/have a definition as described above or hereinafter. The details given for the aryl and heteroaryl groups having 5 to 40 aromatic ring atoms apply here correspondingly.

The abbreviation Ar₃ at each instance is independently an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R² radicals, where the R² radical or the substituents R² has/have a definition as described above or hereinafter. The details given for the aryl and heteroaryl groups having 5 to 40 aromatic ring atoms apply here correspondingly.

The abbreviation Ar at each instance is in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, where the details for the aryl group or heteroaryl group apply correspondingly, as described above. The R# radical or the R# radicals has/have a definition as described above or described hereinafter. The abbreviation Ar at each instance is preferably in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group having 5 to 40 aromatic ring atoms and containing O or S as heteroatom, which may be substituted by one or more R# radicals, where the details for the aryl group, heteroaryl group and R# as described above or hereinafter are applicable correspondingly.

A cyclic alkyl, alkoxy or thioalkyl group in the context of this invention is understood to mean a monocyclic, bicyclic or polycyclic group.

In the context of the present invention, a straight-chain, branched or cyclic C₁- to C₂₀-alkyl group is understood to mean, for example, the methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, s-butyl, t-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, s-pentyl, t-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3-hexyl, neohexyl, cyclohexyl, 1-methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 1-bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1,1-dimethyl-n-hex-1-yl, 1,1-dimethyl-n-hept-1-yl, 1,1-dimethyl-n-oct-1-yl, 1,1-dimethyl-n-dec-1-yl, 1,1-dimethyl-n-dodec-1-yl, 1,1-dimethyl-n-tetradec-1-yl, 1,1-dimethyl-n-hexadec-1-yl, 1,1-dimethyl-n-octadec-1-yl, 1,1-diethyl-n-hex-1-yl, 1,1-diethyl-n-hept-1-yl, 1,1-diethyl-n-oct-1-yl, 1,1-diethyl-n-dec-1-yl, 1,1-diethyl-n-dodec-1-yl, 1,1-diethyl-n-tetradec-1-yl, 1,1-diethyl-n-hexadec-1-yl, 1,1-diethyl-n-octadec-1-yl, 1-(n-propyl)cyclohex-1-yl, 1-(n-butyl)cyclohex-1-yl, 1-(n-hexyl)cyclohex-1-yl, 1-(n-octyl)cyclohex-1-yl and 1-(n-decyl)cyclohex-1-yl radicals.

A straight-chain or branched C₁- to C₂₀-alkoxy group is understood to mean, for example, methoxy, trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy or 2-methylbutoxy.

A straight-chain C₁- to C₂₀-thioalkyl group is understood to mean, for example, S-alkyl groups, for example thiomethyl, 1-thioethyl, 1-thio-i-propyl, 1-thio-n-propyl, 1-thio-i-butyl, 1-thio-n-butyl or 1-thio-t-butyl.

An aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms means O-aryl or O-heteroaryl and means that the aryl or heteroaryl group is bonded via an oxygen atom, where the aryl or heteroaryl group is defined as described above.

An aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms means that an alkyl group as described above is substituted by an aryl group or heteroaryl group, where the aryl or heteroaryl group is defined as described above.

A phosphorescent emitter in the context of the present invention is a compound that exhibits luminescence from an excited state with higher spin multiplicity, i.e. a spin state >1, especially from an excited triplet state. In the context of this application, all luminescent complexes with transition metals or lanthanides are to be regarded as phosphorescent emitters. A more exact definition is given hereinafter.

When the host materials of the light-emitting layer comprising at least one compound of the formula (1) as described above or described as preferred hereinafter and at least one compound of the formula (2) as described above or described hereinafter are used for a phosphorescent emitter, it is preferable when the triplet energy thereof is not significantly less than the triplet energy of the phosphorescent emitter. In respect of the triplet level, it is preferably the case that T₁(emitter)−T₁(matrix)≤0.2 eV, more preferably ≤0.15 eV, most preferably ≤0.1 eV. T₁(matrix) here is the triplet level of the matrix material in the emission layer, this condition being applicable to each of the two matrix materials, and T₁(emitter) is the triplet level of the phosphorescent emitter. If the emission layer contains more than two matrix materials, the abovementioned relationship is preferably also applicable to every further matrix material.

There follows a description of the host material 1 and its preferred embodiments that is/are present in the device of the invention. The preferred embodiments of the host material 1 of the formula (1) are also applicable to the mixture and/or formulation of the invention.

In compounds of the formula (1), the symbol L as linker represents a single bond or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms.

In compounds of the formula (1), the symbol L is preferably a bond or a linker selected from the group of L-1 to L-33

where each W is independently O or S.

The invention therefore further provides the electroluminescent device as described above, wherein the linker L in the host material 1 is selected from a bond or the linkers from the group of L-1 to L-33 as described above.

In compounds of the formula (1), the symbol L in one embodiment is more preferably a bond or a linker selected from L-1 to L-3, L-7, L-21, L-22, L-23, L-25 to L-27 and L-30 to L-33

where each W is independently O or S. W is more preferably O.

Compounds of the formula (1) in which L is preferably a single bond can be described by the formula (1a)

where Y, L₁, X, X₁, Ar₂, R⁰, Ar₃, n, m, o and p have a definition given above or definition given with preference hereinafter.

In compounds of the formula (1), the symbol L₁ as linker represents a single bond or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms.

In compounds of the formula (1), the symbol L₁ is preferably a single bond or a linker selected from the group of L-1 to L-33, as described above. In compounds of the formula (1) or (1a), the symbol L₁ is preferably a single bond or a linker L-2 or L-3, as described above, or more preferably a single bond.

Compounds of the formula (1) in which L₁ is preferably a single bond can be described by the formula (1b)

where Y, L, X, X₁, Ar₂, R⁰, Ar₃, n, m, o and p have a definition given above or definition given with preference hereinafter.

The invention therefore further provides an electroluminescent device as described above, wherein L₁ in the host material 1 is a single bond.

In compounds of the formulae (1), (1a) and (1b) or preferred embodiments of the host material of the formulae (1), (1a) and (1b), the symbol X is CR⁰ or N, where at least one X group is N.

The substituent

therefore has the following definitions, where * indicates the bonding site to the dibenzofuran or dibenzothiophene and L₁, R⁰, o, p, Y and Ar₂ have a definition given above or a definition given as preferred:

In these aforementioned substituents, Y is preferably O.

In host material 1, X is preferably N at two instances and one X is CR⁰, or all X are N. In host material 1, all X are more preferably N, where R⁰ has a definition given above or given hereinafter.

Preferred host materials 1 accordingly correspond to the compounds of the formulae (1), (1a), (1b), (1c) and (1d)

where Y, L, L₁, X, X₁, Ar₂, R⁰, Ar₃, o, p, n and m have a definition given above or definition given with preference above or hereinafter.

R⁰ at each instance is the same or different and is preferably selected from the group of H, D or an unsubstituted or partly or fully deuterated aromatic ring system having 6 to 18 carbon atoms. R⁰ at each instance is preferably H, D or an unsubstituted aromatic ring system having 6 to 18 carbon atoms. R⁰ at each instance is more preferably H or D. R⁰ at each instance is most preferably H.

In compounds of the formulae (1), (1a), (1b), (1c) and (1d), o is preferably 4 when R⁰ is H or D. When R⁰ is not H or D, o is preferably 1 or 2, more preferably 1.

In compounds of the formulae (1), (1a), (1b), (1c) and (1d), p is preferably 3 when R⁰ is H or D. When R⁰ is not H or D, p is preferably 1.

In compounds of the formulae (1), (1a), (1b), (1c) and (1d), m is preferably 3 when R⁰ is H or D. When R⁰ is not H or D, m is preferably 1.

In compounds of the formulae (1), (1a), (1 b), (1c) and (1d), n is preferably 3 when R⁰ is H or D. When R⁰ is not H or D, n is preferably 1.

Compounds of the formula (1) in which X is N at each instance, L is a single bond, R⁰ is H, o is 4 and m, n and p are 3 are represented by the formula (1e)

where Y, L₁, Ar₂, Ar₃ and X₁ have a definition given above or a definition given hereinafter or given with preference above.

Compounds of the formula (1) in which X is N at each instance, L₁ is a single bond, R⁰ is H, o is 4 and m, n and p are 3 and m, n, o and p are 0 are represented by the formula (1f)

where Y, L, Ar₂, Ar₃ and X₁ have a definition given above or a definition given hereinafter or given with preference above.

Compounds of the formula (1e) are preferred embodiments of the compounds of the formula (1) and of the host material 1. In compounds of the formula (1e), preferably one Y is O in the substituent bonded directly to triazine, and the second symbol Y is O or S. In preferred embodiments of the compounds of the formula (1e), both symbols Y are O.

Compounds of the formula (1f) are preferred embodiments of the compounds of the formula (1) and of the host material 1. In compounds of the formula (1f), preferably one Y is O in the substituent bonded directly to triazine, and the second symbol Y is O or S. In preferred embodiments of the compounds of the formula (1f), both symbols Y are O.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), or compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are described as preferred, each Ar₂ is preferably independently an aryl group having 6 to 40 carbon atoms, as described above or described as preferred, which may be substituted by one or more R² radicals, or is a heteroaryl group having 10 to 40 carbon atoms, as described above, which may be substituted by one or more R² radicals. It is possible here for two or more R² radicals bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R³ radicals.

The linkage of the aryl group or heteroaryl group is not limited here, and may be via a carbon atom or via a heteroatom, for example a nitrogen atom.

Ar₂ may preferably be selected from the following groups Ar-1 to Ar-17, where R² and Ar have a definition specified above or specified as preferred, and wherein direct linkage of two heteroatoms to one another by R² or Ar is ruled out:

The dotted line indicates the bonding site to the radical of the formulae (1), (1a), (1 b), (1c), (1d), (1e) or (1f).

More preferably, Ar₂ is Ar-1, Ar-5, Ar-6, Ar-9, Ar-17, more preferably Ar-1, where R² has a definition specified above or specified as preferred hereinafter.

R² in substituents of the formulae Ar-1 to Ar-17, as described above, is preferably selected from the group of H, D, CN, an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R³ radicals, where two substituents R² bonded to the same carbon atom or two adjacent carbon atoms may together form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R³ radicals.

If multiple R² radicals or two R² radicals are bonded to adjacent carbon atoms, the monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system is preferably selected from the group of (S1) to (S4)

where Ar₁ and R³ have a definition given above or hereinafter and # indicates the sites of attachment to the rest of the respective structure, for example to Ar-1 to Ar-17 or Ar₂. Particular preference is given here to selecting (S1) or (S2).

Ar in substituents of the formulae Ar-13 to Ar-16 and (S2), as described above, is preferably phenyl.

The linkage of the dibenzofuran or dibenzothiophene group bonded via the linker L₁ in the compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) is not limited here and may be via any carbon atom. More preferably, the dibenzofuran or dibenzothiophene group in position 2, 3 or 4 is bonded via the linker L₁ to the rest of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f). Most preferably, the dibenzofuran or dibenzothiophene group in position 3 is bonded via the linker L₁ to the rest of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f).

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same or different at each instance and is CH, CR or N, where not more than 3 symbols X₁ can be N.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same or different at each instance and is preferably CH, CR or N, where not more than 1 symbol X₁ is N.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same or different at each instance and is more preferably CH or CR.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same or different at each instance and is more preferably CH or CR, where not more than 3 symbols X₁ can be CR.

In one embodiment of compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ at each instance is CH.

In one embodiment of compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same at each instance and is CH or is CR at two instances, where two adjacent substituents R may together form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals.

If two or more R radicals are bonded to adjacent carbon atoms, the monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system is preferably selected from the group of (S-1) to (S-4)

where Ar₁ and R² have a definition given above or hereinafter and # indicates the attachment sites to the rest of the respective structure, for example to adjacent positions identified by X₁ in compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) to (1f). Particular preference is given here to selecting (S-1) or (S-2).

In one embodiment of compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or preferred compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), X₁ is the same at each instance and is CH or is CR at one instance, where the substituent R together with Ar₃ may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), or compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are described as preferred, each Ar₃ is preferably independently an aryl group having 6 to 40 carbon atoms, as described above or described as preferred, which may be substituted by one or more R² radicals, or is a heteroaryl group having 10 to 40 carbon atoms, as described above, which may be substituted by one or more R² radicals. It is possible here for two or more R² radicals bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R² radicals, or for Ar₃ together with a substituent R in a position X₁ to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), or compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are described as preferred, each Ar₃ is preferably independently an aryl group having 6 to 40 carbon atoms, as described above or described as preferred, which may be substituted by one or more R² radicals, or is a heteroaryl group having 10 to 40 carbon atoms and containing an oxygen atom or a sulfur atom, as described above, which may be substituted by one or more R² radicals. It is possible here for two or more R² radicals bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R² radicals, or for Ar₃ together with a substituent R in a position X₁ to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals.

The linkage of the aryl group or the heteroaryl group is not limited here, but is preferably via a carbon atom.

Ar₃ may preferably be selected from the Ar-1 to Ar-12 groups, as described above, where R² has a definition specified above or specified as preferred.

More preferably, Ar₃ is unsubstituted, i.e. in the preferred groups Ar-1 to Ar-12 for Ar₃, R² is preferably H.

More preferably, Ar₃ is Ar-1 to Ar-4, where R² has a definition specified above or specified as preferred hereinafter.

R² in substituents of the formulae Ar-1 to Ar-12, as described above, is preferably selected from the group of H, CN, an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R³ radicals.

In compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) or compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are described as preferred, the group

is also preferably a group of the formula (5) or (6)

where the dotted line indicates the attachment to the rest of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f).

R³ in compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), as described above or described as preferred, is preferably selected independently at each instance from the group of H, CN, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms in which one or more hydrogen atoms may be replaced by D or CN. R³ in compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f), as described above or described as preferred, is more preferably selected independently at each instance from H, phenyl or deuterated phenyl.

Examples of suitable host materials of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are selected in accordance with the invention and are preferably used in combination with at least one compound of the formula (2) in the electroluminescent device of the invention are the structures given below in table 1.

TABLE 1

Particularly suitable compounds of the formulae (1), (1a), (1b), (1c), (1d), (1e) and (1f) that are used with preference in combination with at least one compound of the formula (2) in the electroluminescent device of the invention are the compounds E1 to E48.

TABLE 2

E1

E2

E3

E4

E5

E6

E7

E8

E9

E10

E11

E12

E13

E14

E15

E16

E17

E18

E19

E20

E21

E22

E23

E24

E25

E26

E27

E28

E29

E30

E31

E32

E33

E34

E35

E36

E37

E38

E39

E40

E41

E42

E43

E44

E45

E46

E47

E48

The preparation of the compounds of the formula (1) or of the preferred compounds from table 1 and of the compounds E1 to E48 is known to those skilled in the art. The compounds can be prepared by synthesis steps known to those skilled in the art, for example bromination, Suzuki coupling, Ullmann coupling, Hartwig-Buchwald coupling, etc. A suitable synthesis method is shown in general terms in scheme 1 below, where the symbols and indices used have the definitions given above.

There follows a description of the host material 2 and its preferred embodiments that is/are present in the device of the invention. The preferred embodiments of the host material 2 of the formula (2) are also applicable to the mixture and/or formulation of the invention.

Host material 2 is at least one compound of the formula (2)

where the symbols and indices used are as follows:

-   A at each instance is independently a group of the formula (3) or     (4),

-   X₂ is the same or different at each instance and is CH, CR¹ or N,     where not more than 2 symbols X₂ can be N; -   * indicates the binding site to the formula (2); -   R¹ is the same or different at each instance and is selected from     the group consisting of CN, a straight-chain alkyl, alkoxy or     thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic     alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an     aromatic or heteroaromatic ring system having 5 to 40 aromatic ring     atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic     ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40     aromatic ring atoms; at the same time, it is possible for two     substituents R¹ bonded to the same carbon atom or to adjacent carbon     atoms to form a monocyclic or polycyclic, aliphatic, aromatic or     heteroaromatic ring system that may be substituted by one or more R²     radicals; -   Ar at each instance is in each case independently an aryl group     which has 6 to 40 aromatic ring atoms and may be substituted by one     or more R# radicals, or a heteroaryl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R#     radicals; -   R# is the same or different at each instance and is selected from     the group consisting of D, F, Cl, Br, I, CN, NO₂, C(═O)R²,     P(═O)(Ar₁)₂, P(Ar₁)₂, B(Ar₁)₂, Si(Ar₁)₃, Si(R²)₃, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20     carbon atoms or an alkenyl group having 2 to 20 carbon atoms, each     of which may be substituted by one or more R² radicals, where one or     more nonadjacent CH₂ groups may be replaced by R²C═CR², Si(R²)₂,     C═O, C═S, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where     one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or     NO₂, an aromatic or heteroaromatic ring system which has 5 to 40     aromatic ring atoms and may be substituted in each case by one or     more R² radicals, an aryloxy or heteroaryloxy group which has 5 to     40 aromatic ring atoms and may be substituted by one or more R²     radicals, or an aralkyl or heteroaralkyl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R²     radicals; -   R² is the same or different at each instance and is selected from     the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar₁)₂, NH₂,     N(R³)₂, C(═O)Ar₁, C(═O)H, C(═O)R³, P(═O)(Ar₁)₂, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40     carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon     atoms, each of which may be substituted by one or more R³ radicals,     where one or more nonadjacent CH₂ groups may be replaced by HC═CH,     R³C═CR³, C≡C, Si(R³)₂, Ge(R³)₂, Sn(R³)₂, C═O, C═S, C═Se, C═NR³,     P(═O)(R³), SO, SO₂, NH, NR³, O, S, CONH or CONR³ and where one or     more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂,     an aromatic or heteroaromatic ring system which has 5 to 60 aromatic     ring atoms and may be substituted in each case by one or more R³     radicals, an aryloxy or heteroaryloxy group which has 5 to 60     aromatic ring atoms and may be substituted by one or more R³     radicals, or a combination of these systems; where it is optionally     possible for two or more adjacent substituents R² to form a     monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring     system which may be substituted by one or more R³ radicals; -   R³ is the same or different at each instance and is selected from     the group consisting of H, D, F, CN, an aliphatic hydrocarbyl     radical having 1 to 20 carbon atoms, or an aromatic or     heteroaromatic ring system having 5 to 30 aromatic ring atoms in     which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I     or CN and which may be substituted by one or more alkyl groups each     having 1 to 4 carbon atoms; at the same time, it is possible for two     or more adjacent R³ substituents together to form a mono- or     polycyclic, aliphatic ring system; -   Ar₁ is the same or different at each instance and is an aromatic or     heteroaromatic ring system which has 5 to 30 aromatic ring atoms and     may be substituted by one or more nonaromatic R³ radicals; at the     same time, two Ar radicals bonded to the same nitrogen atom,     phosphorus atom or boron atom may also be bridged to one another by     a single bond or a bridge selected from N(R³), C(R³)₂, O and S; -   a, b, c at each instance are each independently 0 or 1, where the     sum total of the indices at each instance a+b+c is 1; and -   q, r, s, t at each instance are each independently 0 or 1.

In one embodiment of the invention, for the device of the invention, compounds of the formula (2) as described above are selected, which are used in the light-emitting layer with compounds of the formula (1) as described above or described as preferred, or with the compounds from table 1 or the compounds E1 to E48.

In compounds of the formula (2), a, b, c at each instance are each independently 0 or 1, where the sum total of the indices at each instance a+b+c is 1. c is preferably defined as 1.

Compounds of the formula (2) may be represented by the following formulae (2a), (2b) and (2c):

where A, R¹, q, r, s and t have a definition given above or given hereinafter. Preference is given here to compounds of the formula (2a).

The invention accordingly further provides an organic electroluminescent device as described above or described as preferred, wherein the host material 2 corresponds to a compound of the formula (2a), (2b) or (2c).

R¹ in compounds of the formula (2) and of the formulae (2a) to (2c) or preferred compounds of the formulae (2) and (2a) to (2c), as described above, is the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms; at the same time, it is possible for two substituents R¹ bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals.

If two or more R¹ radicals are bonded to adjacent carbon atoms, the monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system is preferably selected from the group of (S-1) to (S-4)

where Ar₁ and R² have a definition given above or definition given as preferred and # indicates the bonding sites to the rest of the respective structure, for example to adjacent positions identified by X₂ in compounds of the formulae (2), (2a), (2b) and (2c). Particular preference is given here to selecting (S-1) or (S-2).

R¹ in compounds of the formula (2) and of the formulae (2a) to (2c) or preferred compounds of the formulae (2) and (2a) to (2c), as described above, is preferably the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms. The substituent R¹ at each instance is more preferably independently CN or an aryl group having 6 to 40 carbon atoms, as described above. R¹ at each instance is more preferably independently phenyl.

In compounds of the formula (2), (2a), (2b) or (2c), the sum total of the indices q+r+s is preferably 0, 1 or 2, where R¹ has a definition given above.

In compounds of the formula (2), (2a), (2b) or (2c), the sum total of the indices q+r+s is preferably 0 or 1, where R¹ has a definition given above.

In compounds of the formula (2), (2a), (2b) or (2c), q, r and s are preferably 0 or 1. Preferably, q is 1 if the sum total of the indices q+r+s is 1.

Preferably, q, r and s are 0.

In formula (4)

q, r and s are 0 or 1, where R¹ has a definition given above. Preferably, the sum total of the indices q+r+s in formula (4) is 0 or 1. In formula (4), q, r and s are more preferably 0.

In formula (3)

t is in each case independently preferably 0 or 1. In formula (3), t is preferably the same and is 0.

In compounds of the formulae (2), (2a), (2b) and (2c) or preferred compounds of the formulae (2), (2a), (2b) and (2c), X₂ is the same or different at each instance and is CH, CR¹ or N, where not more than 2 symbols X₂ can be N.

In compounds of the formulae (2), (2a), (2b) and (2c) or preferred compounds of the formulae (2), (2a), (2b) and (2c), X₂ is preferably the same or different at each instance and is CH, CR¹ or N, where not more than 1 symbol X₂ can be N.

In compounds of the formulae (2), (2a), (2b) and (2c) or preferred compounds of the formulae (2), (2a), (2b) and (2c), X₂ is more preferably the same or different at each instance and is CH at two instances and CR¹ at two instances, or CH at three instances and CR¹ at one instance, where the substituents R¹ at each instance independently have a definition given above.

Ar at each instance is in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, where the R# radical has a definition given above or given with preference hereinafter.

Ar at each instance is preferably in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group having 5 to 40 aromatic ring atoms and containing O or S as heteroatom, which may be substituted by one or more R# radicals, where the R# radical has a definition given above or given with preference.

Ar at each instance is preferably an aryl group which has 6 to 18 carbon atoms and may be substituted by one or more R# radicals, or dibenzofuranyl or dibenzothiophenyl which may be substituted by one or more R# radicals, where the R# radical has a definition given above or given with preference hereinafter.

Ar is more preferably phenyl, dibenzofuran-substituted phenyl, dibenzothiophene-substituted phenyl, 1,3-biphenyl, 1,4-biphenyl, terphenyl, quaterphenyl, naphthyl, fluorenyl, 9,9-diphenylfluorenyl, bispirofluorenyl, triphenylenyl, dibenzofuranyl, phenyl-substituted dibenzofuranyl, dibenzothiophenyl or phenyl-substituted dibenzothiophenyl. Ar is most preferably phenyl, 1,3-biphenyl, 1,4-biphenyl, naphth-2-yl or triphenyl-2-yl.

In compounds of the formulae (2), (2a), (2b) and (2c) or preferred compounds of the formulae (2), (2a), (2b) and (2c), R# is the same or different at each instance and is preferably selected from the group consisting of D, CN and an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R² radicals.

In compounds of the formulae (2), (2a), (2b) and (2c) or preferred compounds of the formulae (2), (2a), (2b) and (2c), R# is the same or different at each instance and is preferably an unsubstituted aromatic ring system having 5 to 20 aromatic ring atoms, preferably phenyl.

In a preferred embodiment of the invention, A conforms to the formula (4) as described above or with substituents as described as preferred.

In a preferred embodiment of the invention, A conforms to the formula (3) as described above or with substituents as described as preferred.

Compounds of the formula (2), (2a), (2b) or (2c) where A conforms to the formula (3) and q, r, s and t are 0 may be represented by the formulae (2d) and (2e)

where X₂ and Ar have a definition given above or given as preferred.

The invention accordingly further provides an organic electroluminescent device as described above or described as preferred, wherein the at least one compound of the formula (2) corresponds to a compound of the formula (2d) or of the formula (2e).

In a preferred embodiment of the compounds of the formula (2), (2a), (2b), (2c), (2d) or (2e), the substituents of the formulae (3) and (4) are each joined to one another in the 2 position or 5 position of the indolo[3,2,1-jk]carbazole, as shown in schematic form below, where the dotted line indicates the linkage to the substituents of the formulae (3) and (4):

Examples of suitable host materials of the formulae (2), (2a), (2b), (2c), (2d) and (2e) that are selected in accordance with the invention and are preferably used in combination with at least one compound of the formula (1) in the electroluminescent device of the invention are the structures given below in table 3

TABLE 3

Particularly suitable compounds of the formula (2) that are preferably used in combination with at least one compound of the formula (1) in the electroluminescent device of the invention are the compounds H1 to H21 of table 4.

TABLE 4

H1

H2

H3

H4

H5

H6

H7

H8

H9

H10

H11

H12

H13

H14

H15

H16

H17

H18

H19

H20

H21

Very particularly suitable compounds of the formula (2) that are used in the electroluminescent device of the invention in combination with at least one compound of the formula (1) are the compounds H1, H3, H4, H5, H6, H7, H8, H11 and H12.

The preparation of the compounds of the formula (2) or of the preferred compounds of the formulae (2), (2a), (2b), (2c), (2d) and (2e) and of the compounds from table 3 and compounds H1 to H21 is known to the person skilled in the art. The compounds can be prepared by synthesis steps known to those skilled in the art, for example bromination, Suzuki coupling, Ullmann coupling, Hartwig-Buchwald coupling, etc. A suitable synthesis method is shown in general terms in scheme 2 below, where the symbols and indices used have the definitions given above.

The aforementioned host materials of the formula (1) and the embodiments thereof that are described as preferred or the compounds from table 1 and the compounds E1 to E48 can be combined as desired in the device of the invention with the host materials of the formulae (2), (2a), (2b), (2c), (2d) and (2e) mentioned and the embodiments thereof that are described as preferred or the compounds from table 3 or the compounds H1 to H21.

The invention likewise further provides mixtures comprising at least one compound of the formula (1) as host material 1 and at least one compound of the formula (2) as host material 2

where the symbols and indices used are as follows:

-   X is the same or different at each instance and is CR⁰ or N, where     at least one symbol X is N; -   X₁ is the same or different at each instance and is CH, CR or N,     where not more than 3 symbols X₁ can be N; -   X₂ is the same or different at each instance and is CH, CR¹ or N,     where not more than 2 symbols X₂ can be N; -   Y is the same or different at each instance and is selected from O     and S; -   L and L₁ are the same or different at each instance and are a single     bond or an aromatic or heteroaromatic ring system having 5 to 30     aromatic ring atoms; -   R⁰ at each instance is independently H, D or an unsubstituted or     partly or fully deuterated aromatic ring system having 6 to 18     carbon atoms; -   R and R# are the same or different at each instance and are selected     from the group consisting of D, F, Cl, Br, I, CN, NO₂, C(═O)R²,     P(═O)(Ar₁)₂, P(Ar₁)₂, B(Ar₁)₂, Si(Ar₁)₃, Si(R²)₃, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20     carbon atoms or an alkenyl group having 2 to 20 carbon atoms, each     of which may be substituted by one or more R² radicals, where one or     more nonadjacent CH₂ groups may be replaced by R²C═CR², Si(R²)₂,     C═O, C═S, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where     one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or     NO₂, an aromatic or heteroaromatic ring system which has 5 to 40     aromatic ring atoms and may be substituted in each case by one or     more R² radicals, an aryloxy or heteroaryloxy group which has 5 to     40 aromatic ring atoms and may be substituted by one or more R²     radicals, or an aralkyl or heteroaralkyl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R²     radicals; at the same time, it is possible for two substituents R     bonded to the same carbon atom or to adjacent carbon atoms or for     one substituent R together with Ar₃ to form a monocyclic or     polycyclic, aliphatic, aromatic or heteroaromatic ring system which     may be substituted by one or more R² radicals; -   R¹ is the same or different at each instance and is selected from     the group consisting of CN, a straight-chain alkyl, alkoxy or     thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic     alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an     aromatic or heteroaromatic ring system having 5 to 40 aromatic ring     atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic     ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40     aromatic ring atoms; at the same time, it is possible for two     substituents R¹ bonded to the same carbon atom or to adjacent carbon     atoms to form a monocyclic or polycyclic, aliphatic, aromatic or     heteroaromatic ring system that may be substituted by one or more R²     radicals; -   R² is the same or different at each instance and is selected from     the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar₁)₂, NH₂,     N(R³)₂, C(═O)Ar₁, C(═O)H, C(═O)R³, P(═O)(Ar₁)₂, a straight-chain     alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a     branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40     carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon     atoms, each of which may be substituted by one or more R³ radicals,     where one or more nonadjacent CH₂ groups may be replaced by HC═CH,     R³C═CR³, C≡C, Si(R³)₂, Ge(R³)₂, Sn(R³)₂, C═O, C═S, C═Se, C═NR³,     P(═O)(R³), SO, SO₂, NH, NR³, O, S, CONH or CONR³ and where one or     more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂,     an aromatic or heteroaromatic ring system which has 5 to 60 aromatic     ring atoms and may be substituted in each case by one or more R³     radicals, an aryloxy or heteroaryloxy group which has 5 to 60     aromatic ring atoms and may be substituted by one or more R³     radicals, or a combination of these systems; where it is optionally     possible for two or more adjacent substituents R² to form a     monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring     system which may be substituted by one or more R³ radicals; -   R³ is the same or different at each instance and is selected from     the group consisting of H, D, F, CN, an aliphatic hydrocarbyl     radical having 1 to 20 carbon atoms, or an aromatic or     heteroaromatic ring system having 5 to 30 aromatic ring atoms in     which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I     or CN and which may be substituted by one or more alkyl groups each     having 1 to 4 carbon atoms; at the same time, it is possible for two     or more adjacent R³ substituents together to form a mono- or     polycyclic, aliphatic ring system; -   Ar₁ is the same or different at each instance and is an aromatic or     heteroaromatic ring system which has 5 to 30 aromatic ring atoms and     may be substituted by one or more nonaromatic R³ radicals; at the     same time, two Ar₁ radicals bonded to the same nitrogen atom,     phosphorus atom or boron atom may also be bridged to one another by     a single bond or a bridge selected from N(R³), C(R³)₂, O and S; -   Ar₂ at each instance is independently an aryl or heteroaryl group     which has 5 to 40 aromatic ring atoms and may be substituted by one     or more R² radicals; -   Ar₃ at each instance is independently an aromatic ring system having     6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5     to 40 aromatic ring atoms, which may be substituted by one or more     R² radicals; -   A at each instance is independently a group of the formula (3) or     (4),

-   Ar at each instance is in each case independently an aryl group     which has 6 to 40 aromatic ring atoms and may be substituted by one     or more R# radicals, or a heteroaryl group which has 5 to 40     aromatic ring atoms and may be substituted by one or more R#     radicals; -   * indicates the binding site to the formula (2); -   a, b, c at each instance are each independently 0 or 1, where the     sum total of the indices at each instance a+b+c is 1; -   o is 1, 2, 3 or 4; -   n, m and p at each instance are independently 1, 2 or 3; and -   q, r, s, t at each instance are each independently 0 or 1.

The details with regard to the host materials of the formulae (1) and (2) and the preferred embodiments thereof are correspondingly also applicable to the mixture of the invention.

Particularly preferred mixtures of the host materials of the formula (1) with the host materials of the formula (2) for the device of the invention are obtained by combination of the compounds E1 to E48 with the compounds from table 3.

Very particularly preferred mixtures of the host materials of the formula (1) with the host materials of the formula (2) for the device of the invention are obtained by combination of the compounds E1 to E48 with the compounds H1 to H21, as shown hereinafter in table 5.

TABLE 5 M1 E1 H1 M2 E2 H1 M3 E3 H1 M4 E4 H1 M5 E5 H1 M6 E6 H1 M7 E7 H1 M8 E8 H1 M9 E9 H1 M10 E10 H1 M11 E11 H1 M12 E12 H1 M13 E13 H1 M14 E14 H1 M15 E15 H1 M16 E16 H1 M17 E17 H1 M18 E18 H1 M19 E19 H1 M20 E20 H1 M21 E21 H1 M22 E22 H1 M23 E23 H1 M24 E24 H1 M25 E25 H1 M26 E26 H1 M27 E27 H1 M28 E28 H1 M29 E29 H1 M30 E30 H1 M31 E31 H1 M32 E32 H1 M33 E33 H1 M34 E34 H1 M35 E35 H1 M36 E36 H1 M37 E37 H1 M38 E38 H1 M39 E39 H1 M40 E1 H2 M41 E2 H2 M42 E3 H2 M43 E4 H2 M44 E5 H2 M45 E6 H2 M46 E7 H2 M47 E8 H2 M48 E9 H2 M49 E10 H2 M50 E11 H2 M51 E12 H2 M52 E13 H2 M53 E14 H2 M54 E15 H2 M55 E16 H2 M56 E17 H2 M57 E18 H2 M58 E19 H2 M59 E20 H2 M60 E21 H2 M61 E22 H2 M62 E23 H2 M63 E24 H2 M64 E25 H2 M65 E26 H2 M66 E27 H2 M67 E28 H2 M68 E29 H2 M69 E30 H2 M70 E31 H2 M71 E32 H2 M72 E33 H2 M73 E34 H2 M74 E35 H2 M75 E36 H2 M76 E37 H2 M77 E38 H2 M78 E39 H2 M79 E1 H3 M80 E2 H3 M81 E3 H3 M82 E4 H3 M83 E5 H3 M84 E6 H3 M85 E7 H3 M86 E8 H3 M87 E9 H3 M88 E10 H3 M89 E11 H3 M90 E12 H3 M91 E13 H3 M92 E14 H3 M93 E15 H3 M94 E16 H3 M95 E17 H3 M96 E18 H3 M97 E19 H3 M98 E20 H3 M99 E21 H3 M100 E22 H3 M101 E23 H3 M102 E24 H3 M103 E25 H3 M104 E26 H3 M105 E27 H3 M106 E28 H3 M107 E29 H3 M108 E30 H3 M109 E31 H3 M110 E32 H3 M111 E33 H3 M112 E34 H3 M113 E35 H3 M114 E36 H3 M115 E37 H3 M116 E38 H3 M117 E39 H3 M118 E1 H4 M119 E2 H4 M120 E3 H4 M121 E4 H4 M122 E5 H4 M123 E6 H4 M124 E7 H4 M125 E8 H4 M126 E9 H4 M127 E10 H4 M128 E11 H4 M129 E12 H4 M130 E13 H4 M131 E14 H4 M132 E15 H4 M133 E16 H4 M134 E17 H4 M135 E18 H4 M136 E19 H4 M137 E20 H4 M138 E21 H4 M139 E22 H4 M140 E23 H4 M141 E24 H4 M142 E25 H4 M143 E26 H4 M144 E27 H4 M145 E28 H4 M146 E29 H4 M147 E30 H4 M148 E31 H4 M149 E32 H4 M150 E33 H4 M151 E34 H4 M152 E35 H4 M153 E36 H4 M154 E37 H4 M155 E38 H4 M156 E39 H4 M157 E1 H5 M158 E2 H5 M159 E3 H5 M160 E4 H5 M161 E5 H5 M162 E6 H5 M163 E7 H5 M164 E8 H5 M165 E9 H5 M166 E10 H5 M167 E11 H5 M168 E12 H5 M169 E13 H5 M170 E14 H5 M171 E15 H5 M172 E16 H5 M173 E17 H5 M174 E18 H5 M175 E19 H5 M176 E20 H5 M177 E21 H5 M178 E22 H5 M179 E23 H5 M180 E24 H5 M181 E25 H5 M182 E26 H5 M183 E27 H5 M184 E28 H5 M185 E29 H5 M186 E30 H5 M187 E31 H5 M188 E32 H5 M189 E33 H5 M190 E34 H5 M191 E35 H5 M192 E36 H5 M193 E37 H5 M194 E38 H5 M195 E39 H5 M196 E1 H6 M197 E2 H6 M198 E3 H6 M199 E4 H6 M200 E5 H6 M201 E6 H6 M202 E7 H6 M203 E8 H6 M204 E9 H6 M205 E10 H6 M206 E11 H6 M207 E12 H6 M208 E13 H6 M209 E14 H6 M210 E15 H6 M211 E16 H6 M212 E17 H6 M213 E18 H6 M214 E19 H6 M215 E20 H6 M216 E21 H6 M217 E22 H6 M218 E23 H6 M219 E24 H6 M220 E25 H6 M221 E26 H6 M222 E27 H6 M223 E28 H6 M224 E29 H6 M225 E30 H6 M226 E31 H6 M227 E32 H6 M228 E33 H6 M229 E34 H6 M230 E35 H6 M231 E36 H6 M232 E37 H6 M233 E38 H6 M234 E39 H6 M235 E1 H7 M236 E2 H7 M237 E3 H7 M238 E4 H7 M239 E5 H7 M240 E6 H7 M241 E7 H7 M242 E8 H7 M243 E9 H7 M244 E10 H7 M245 E11 H7 M246 E12 H7 M247 E13 H7 M248 E14 H7 M249 E15 H7 M250 E16 H7 M251 E17 H7 M252 E18 H7 M253 E19 H7 M254 E20 H7 M255 E21 H7 M256 E22 H7 M257 E23 H7 M258 E24 H7 M259 E25 H7 M260 E26 H7 M261 E27 H7 M262 E28 H7 M263 E29 H7 M264 E30 H7 M265 E31 H7 M266 E32 H7 M267 E33 H7 M268 E34 H7 M269 E35 H7 M270 E36 H7 M271 E37 H7 M272 E38 H7 M273 E39 H7 M274 E1 H8 M275 E2 H8 M276 E3 H8 M277 E4 H8 M278 E5 H8 M279 E6 H8 M280 E7 H8 M281 E8 H8 M282 E9 H8 M283 E10 H8 M284 E11 H8 M285 E12 H8 M286 E13 H8 M287 E14 H8 M288 E15 H8 M289 E16 H8 M290 E17 H8 M291 E18 H8 M292 E19 H8 M293 E20 H8 M294 E21 H8 M295 E22 H8 M296 E23 H8 M297 E24 H8 M298 E25 H8 M299 E26 H8 M300 E27 H8 M301 E28 H8 M302 E29 H8 M303 E30 H8 M304 E31 H8 M305 E32 H8 M306 E33 H8 M307 E34 H8 M308 E35 H8 M309 E36 H8 M310 E37 H8 M311 E38 H8 M312 E39 H8 M313 E1 H9 M314 E2 H9 M315 E3 H9 M316 E4 H9 M317 E5 H9 M318 E6 H9 M319 E7 H9 M320 E8 H9 M321 E9 H9 M322 E10 H9 M323 E11 H9 M324 E12 H9 M325 E13 H9 M326 E14 H9 M327 E15 H9 M328 E16 H9 M329 E17 H9 M330 E18 H9 M331 E19 H9 M332 E20 H9 M333 E21 H9 M334 E22 H9 M335 E23 H9 M336 E24 H9 M337 E25 H9 M338 E26 H9 M339 E27 H9 M340 E28 H9 M341 E29 H9 M342 E30 H9 M343 E31 H9 M344 E32 H9 M345 E33 H9 M346 E34 H9 M347 E35 H9 M348 E36 H9 M349 E37 H9 M350 E38 H9 M351 E39 H9 M352 E1 H10 M353 E2 H10 M354 E3 H10 M355 E4 H10 M356 E5 H10 M357 E6 H10 M358 E7 H10 M359 E8 H10 M360 E9 H10 M361 E10 H10 M362 E11 H10 M363 E12 H10 M364 E13 H10 M365 E14 H10 M366 E15 H10 M367 E16 H10 M368 E17 H10 M369 E18 H10 M370 E19 H10 M371 E20 H10 M372 E21 H10 M373 E22 H10 M374 E23 H10 M375 E24 H10 M376 E25 H10 M377 E26 H10 M378 E27 H10 M379 E28 H10 M380 E29 H10 M381 E30 H10 M382 E31 H10 M383 E32 H10 M384 E33 H10 M385 E34 H10 M386 E35 H10 M387 E36 H10 M388 E37 H10 M389 E38 H10 M390 E39 H10 M391 E1 H11 M392 E2 H11 M393 E3 H11 M394 E4 H11 M395 E5 H11 M396 E6 H11 M397 E7 H11 M398 E8 H11 M399 E9 H11 M400 E10 H11 M401 E11 H11 M402 E12 H11 M403 E13 H11 M404 E14 H11 M405 E15 H11 M406 E16 H11 M407 E17 H11 M408 E18 H11 M409 E19 H11 M410 E20 H11 M411 E21 H11 M412 E22 H11 M413 E23 H11 M414 E24 H11 M415 E25 H11 M416 E26 H11 M417 E27 H11 M418 E28 H11 M419 E29 H11 M420 E30 H11 M421 E31 H11 M422 E32 H11 M423 E33 H11 M424 E34 H11 M425 E35 H11 M426 E36 H11 M427 E37 H11 M428 E38 H11 M429 E39 H11 M430 E1 H12 M431 E2 H12 M432 E3 H12 M433 E4 H12 M434 E5 H12 M435 E6 H12 M436 E7 H12 M437 E8 H12 M438 E9 H12 M439 E10 H12 M440 E11 H12 M441 E12 H12 M442 E13 H12 M443 E14 H12 M444 E15 H12 M445 E16 H12 M446 E17 H12 M447 E18 H12 M448 E19 H12 M449 E20 H12 M450 E21 H12 M451 E22 H12 M452 E23 H12 M453 E24 H12 M454 E25 H12 M455 E26 H12 M456 E27 H12 M457 E28 H12 M458 E29 H12 M459 E30 H12 M460 E31 H12 M461 E32 H12 M462 E33 H12 M463 E34 H12 M464 E35 H12 M465 E36 H12 M466 E37 H12 M467 E38 H12 M468 E39 H12 M469 E1 H13 M470 E2 H13 M471 E3 H13 M472 E4 H13 M473 E5 H13 M474 E6 H13 M475 E7 H13 M476 E8 H13 M477 E9 H13 M478 E10 H13 M479 E11 H13 M480 E12 H13 M481 E13 H13 M482 E14 H13 M483 E15 H13 M484 E16 H13 M485 E17 H13 M486 E18 H13 M487 E19 H13 M488 E20 H13 M489 E21 H13 M490 E22 H13 M491 E23 H13 M492 E24 H13 M493 E25 H13 M494 E26 H13 M495 E27 H13 M496 E28 H13 M497 E29 H13 M498 E30 H13 M499 E31 H13 M500 E32 H13 M501 E33 H13 M502 E34 H13 M503 E35 H13 M504 E36 H13 M505 E37 H13 M506 E38 H13 M507 E39 H13 M508 E1 H14 M509 E2 H14 M510 E3 H14 M511 E4 H14 M512 E5 H14 M513 E6 H14 M514 E7 H14 M515 E8 H14 M516 E9 H14 M517 E10 H14 M518 E11 H14 M519 E12 H14 M520 E13 H14 M521 E14 H14 M522 E15 H14 M523 E16 H14 M524 E17 H14 M525 E18 H14 M526 E19 H14 M527 E20 H14 M528 E21 H14 M529 E22 H14 M530 E23 H14 M531 E24 H14 M532 E25 H14 M533 E26 H14 M534 E27 H14 M535 E28 H14 M536 E29 H14 M537 E30 H14 M538 E31 H14 M539 E32 H14 M540 E33 H14 M541 E34 H14 M542 E35 H14 M543 E36 H14 M544 E37 H14 M545 E38 H14 M546 E39 H14 M547 E1 H15 M548 E2 H15 M549 E3 H15 M550 E4 H15 M551 E5 H15 M552 E6 H15 M553 E7 H15 M554 E8 H15 M555 E9 H15 M556 E10 H15 M557 E11 H15 M558 E12 H15 M559 E13 H15 M560 E14 H15 M561 E15 H15 M562 E16 H15 M563 E17 H15 M564 E18 H15 M565 E19 H15 M566 E20 H15 M567 E21 H15 M568 E22 H15 M569 E23 H15 M570 E24 H15 M571 E25 H15 M572 E26 H15 M573 E27 H15 M574 E28 H15 M575 E29 H15 M576 E30 H15 M577 E31 H15 M578 E32 H15 M579 E33 H15 M580 E34 H15 M581 E35 H15 M582 E36 H15 M583 E37 H15 M584 E38 H15 M585 E39 H15 M586 E1 H16 M587 E2 H16 M588 E3 H16 M589 E4 H16 M590 E5 H16 M591 E6 H16 M592 E7 H16 M593 E8 H16 M594 E9 H16 M595 E10 H16 M596 E11 H16 M597 E12 H16 M598 E13 H16 M599 E14 H16 M600 E15 H16 M601 E16 H16 M602 E17 H16 M603 E18 H16 M604 E19 H16 M605 E20 H16 M606 E21 H16 M607 E22 H16 M608 E23 H16 M609 E24 H16 M610 E25 H16 M611 E26 H16 M612 E27 H16 M613 E28 H16 M614 E29 H16 M615 E30 H16 M616 E31 H16 M617 E32 H16 M618 E33 H16 M619 E34 H16 M620 E35 H16 M621 E36 H16 M622 E37 H16 M623 E38 H16 M624 E39 H16 M625 E1 H17 M626 E2 H17 M627 E3 H17 M628 E4 H17 M629 E5 H17 M630 E6 H17 M631 E7 H17 M632 E8 H17 M633 E9 H17 M634 E10 H17 M635 E11 H17 M636 E12 H17 M637 E13 H17 M638 E14 H17 M639 E15 H17 M640 E16 H17 M641 E17 H17 M642 E18 H17 M643 E19 H17 M644 E20 H17 M645 E21 H17 M646 E22 H17 M647 E23 H17 M648 E24 H17 M649 E25 H17 M650 E26 H17 M651 E27 H17 M652 E28 H17 M653 E29 H17 M654 E30 H17 M655 E31 H17 M656 E32 H17 M657 E33 H17 M658 E34 H17 M659 E35 H17 M660 E36 H17 M661 E37 H17 M662 E38 H17 M663 E39 H17 M664 E1 H18 M665 E2 H18 M666 E3 H18 M667 E4 H18 M668 E5 H18 M669 E6 H18 M670 E7 H18 M671 E8 H18 M672 E9 H18 M673 E10 H18 M674 E11 H18 M675 E12 H18 M676 E13 H18 M677 E14 H18 M678 E15 H18 M679 E16 H18 M680 E17 H18 M681 E18 H18 M682 E19 H18 M683 E20 H18 M684 E21 H18 M685 E22 H18 M686 E23 H18 M687 E24 H18 M688 E25 H18 M689 E26 H18 M690 E27 H18 M691 E28 H18 M692 E29 H18 M693 E30 H18 M694 E31 H18 M695 E32 H18 M696 E33 H18 M697 E34 H18 M698 E35 H18 M699 E36 H18 M700 E37 H18 M701 E38 H18 M702 E39 H18 M703 E1 H19 M704 E2 H19 M705 E3 H19 M706 E4 H19 M707 E5 H19 M708 E6 H19 M709 E7 H19 M710 E8 H19 M711 E9 H19 M712 E10 H19 M713 E11 H19 M714 E12 H19 M715 E13 H19 M716 E14 H19 M717 E15 H19 M718 E16 H19 M719 E17 H19 M720 E18 H19 M721 E19 H19 M722 E20 H19 M723 E21 H19 M724 E22 H19 M725 E23 H19 M726 E24 H19 M727 E25 H19 M728 E26 H19 M729 E27 H19 M730 E28 H19 M731 E29 H19 M732 E30 H19 M733 E31 H19 M734 E32 H19 M735 E33 H19 M736 E34 H19 M737 E35 H19 M738 E36 H19 M739 E37 H19 M740 E38 H19 M741 E39 H19 M742 E1 H20 M743 E2 H20 M744 E3 H20 M745 E4 H20 M746 E5 H20 M747 E6 H20 M748 E7 H20 M749 E8 H20 M750 E9 H20 M751 E10 H20 M752 E11 H20 M753 E12 H20 M754 E13 H20 M755 E14 H20 M756 E15 H20 M757 E16 H20 M758 E17 H20 M759 E18 H20 M760 E19 H20 M761 E20 H20 M762 E21 H20 M763 E22 H20 M764 E23 H20 M765 E24 H20 M766 E25 H20 M767 E26 H20 M768 E27 H20 M769 E28 H20 M770 E29 H20 M771 E30 H20 M772 E31 H20 M773 E32 H20 M774 E33 H20 M775 E34 H20 M776 E35 H20 M777 E36 H20 M778 E37 H20 M779 E38 H20 M780 E39 H20 M781 E1 H21 M782 E2 H21 M783 E3 H21 M784 E4 H21 M785 E5 H21 M786 E6 H21 M787 E7 H21 M788 E8 H21 M789 E9 H21 M790 E10 H21 M791 E11 H21 M792 E12 H21 M793 E13 H21 M794 E14 H21 M795 E15 H21 M796 E16 H21 M797 E17 H21 M798 E18 H21 M799 E19 H21 M800 E20 H21 M801 E21 H21 M802 E22 H21 M803 E23 H21 M804 E24 H21 M805 E25 H21 M806 E26 H21 M807 E27 H21 M808 E28 H21 M809 E29 H21 M810 E30 H21 M811 E31 H21 M812 E32 H21 M813 E33 H21 M814 E34 H21 M815 E35 H21 M816 E36 H21 M817 E37 H21 M818 E38 H21 M819 E39 H21 M820 E40 H1 M821 E40 H2 M822 E40 H3 M823 E40 H4 M824 E40 H5 M825 E40 H6 M826 E40 H7 M827 E40 H8 M828 E40 H9 M829 E40 H10 M830 E40 H11 M831 E40 H12 M832 E40 H13 M833 E40 H14 M834 E40 H15 M835 E40 H16 M836 E40 H17 M837 E40 H18 M838 E40 H19 M839 E40 H20 M840 E40 H21 M841 E41 H1 M842 E41 H2 M843 E41 H3 M844 E41 H4 M845 E41 H5 M846 E41 H6 M847 E41 H7 M848 E41 H8 M849 E41 H9 M850 E41 H10 M851 E41 H11 M852 E41 H12 M853 E41 H13 M854 E41 H14 M855 E41 H15 M856 E41 H16 M857 E41 H17 M858 E41 H18 M859 E41 H19 M860 E41 H20 M861 E41 H21 M862 E42 H1 M863 E42 H2 M864 E42 H3 M865 E42 H4 M866 E42 H5 M867 E42 H6 M868 E42 H7 M869 E42 H8 M870 E42 H9 M871 E42 H10 M872 E42 H11 M873 E42 H12 M874 E42 H13 M875 E42 H14 M876 E42 H15 M877 E42 H16 M878 E42 H17 M879 E42 H18 M880 E42 H19 M881 E42 H20 M882 E42 H21 M883 E43 H1 M884 E43 H2 M885 E43 H3 M886 E43 H4 M887 E43 H5 M888 E43 H6 M889 E43 H7 M890 E43 H8 M891 E43 H9 M892 E43 H10 M893 E43 H11 M894 E43 H12 M895 E43 H13 M896 E43 H14 M897 E43 H15 M898 E43 H16 M899 E43 H17 M900 E43 H18 M901 E43 H19 M902 E43 H20 M903 E43 H21 M904 E44 H1 M905 E44 H2 M906 E44 H3 M907 E44 H4 M908 E44 H5 M909 E44 H6 M910 E44 H7 M911 E44 H8 M912 E44 H9 M913 E44 H10 M914 E44 H11 M915 E44 H12 M916 E44 H13 M917 E44 H14 M918 E44 H15 M919 E44 H16 M920 E44 H17 M921 E44 H18 M922 E44 H19 M923 E44 H20 M924 E44 H21 M925 E45 H1 M926 E45 H2 M927 E45 H3 M928 E45 H4 M929 E45 H5 M930 E45 H6 M931 E45 H7 M932 E45 H8 M933 E45 H9 M934 E45 H10 M935 E45 H11 M936 E45 H12 M937 E45 H13 M938 E45 H14 M939 E45 H15 M940 E45 H16 M941 E45 H17 M942 E45 H18 M943 E45 H19 M944 E45 H20 M945 E45 H21 M946 E46 H1 M947 E46 H2 M948 E46 H3 M949 E46 H4 M950 E46 H5 M951 E46 H6 M952 E46 H7 M953 E46 H8 M954 E46 H9 M955 E46 H10 M956 E46 H11 M957 E46 H12 M958 E46 H13 M959 E46 H14 M960 E46 H15 M961 E46 H16 M962 E46 H17 M963 E46 H18 M964 E46 H19 M965 E46 H20 M966 E46 H21 M967 E47 H1 M968 E47 H2 M969 E47 H3 M970 E47 H4 M971 E47 H5 M972 E47 H6 M973 E47 H7 M974 E47 H8 M975 E47 H9 M976 E47 H10 M977 E47 H11 M978 E47 H12 M979 E47 H13 M980 E47 H14 M981 E47 H15 M982 E47 H16 M983 E47 H17 M984 E47 H18 M985 E47 H19 M986 E47 H20 M987 E47 H21 M988 E48 H1 M989 E48 H2 M990 E48 H3 M991 E48 H4 M992 E48 H5 M993 E48 H6 M994 E48 H7 M995 E48 H8 M996 E48 H9 M997 E48 H10 M998 E48 H11 M999 E48 H12 M1000 E48 H13 M1001 E48 H14 M1002 E48 H15 M1003 E48 H16 M1004 E48 H17 M1005 E48 H18 M1006 E48 H19 M1007 E48 H20 M1008 E48 H21.

The concentration of the electron-transporting host material of the formula (1) as described above or described as preferred in the mixture of the invention or in the light-emitting layer of the device of the invention is in the range from 5% by weight to 90% by weight, preferably in the range from 10% by weight to 85% by weight, more preferably in the range from 20% by weight to 85% by weight, even more preferably in the range from 30% by weight to 80% by weight, very especially preferably in the range from 20% by weight to 60% by weight and most preferably in the range from 30% by weight to 50% by weight, based on the overall mixture or based on the overall composition of the light-emitting layer.

The concentration of the hole-transporting host material of the formula (2) as described above or described as preferred in the mixture of the invention or in the light-emitting layer of the device of the invention is in the range from 10% by weight to 95% by weight, preferably in the range from 15% by weight to 90% by weight, more preferably in the range from 15% by weight to 80% by weight, even more preferably in the range from 20% by weight to 70% by weight, very especially preferably in the range from 40% by weight to 80% by weight and most preferably in the range from 50% by weight to 70% by weight, based on the overall mixture or based on the overall composition of the light-emitting layer.

The present invention also relates to a mixture which, as well as the aforementioned host materials 1 and 2, as described above or described with preference, especially mixtures M1 to M1008, also contains at least one phosphorescent emitter.

The present invention also relates to an organic electroluminescent device as described above or described with preference, wherein the light-emitting layer, as well as the aforementioned host materials 1 and 2, as described above or described with preference, especially material combinations M1 to M1008, also comprises at least one phosphorescent emitter.

The term “phosphorescent emitters” typically encompasses compounds where the light is emitted through a spin-forbidden transition from an excited state having higher spin multiplicity, i.e. a spin state >1, for example through a transition from a triplet state or a state having an even higher spin quantum number, for example a quintet state. This is preferably understood to mean a transition from a triplet state.

Suitable phosphorescent emitters (=triplet emitters) are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, more preferably greater than 56 and less than 80, especially a metal having this atomic number. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing iridium or platinum. In the context of the present invention, all luminescent compounds containing the abovementioned metals are regarded as phosphorescent emitters.

In general, all phosphorescent complexes as used for phosphorescent OLEDs according to the prior art and as known to those skilled in the art in the field of organic electroluminescent devices are suitable.

Examples of the above-described emitters can be found in applications WO 2016/015815, WO 00/70655, WO 2001/41512, WO 2002/02714, WO 2002/15645, EP 1191613, EP 1191612, EP 1191614, WO 05/033244, WO 05/019373, US 2005/0258742, WO 2009/146770, WO 2010/015307, WO 2010/031485, WO 2010/054731, WO 2010/054728, WO 2010/086089, WO 2010/099852, WO 2010/102709, WO 2011/032626, WO 2011/066898, WO 2011/157339, WO 2012/007086, WO 2014/008982, WO 2014/023377, WO 2014/094961, WO 2014/094960, WO 2015/036074, WO 2015/104045, WO 2015/117718, WO 2016/015815, WO 2016/124304, WO 2017/032439, WO 2015/036074, WO 2015/117718 and WO 2016/015815.

Preferred phosphorescent emitters according to the present invention conform to the formula (III)

where the symbols and indices for this formula (III) are defined as follows:

n+m is 3, n is 1 or 2, m is 2 or 1,

X is N or CR,

R is H, D or a branched or linear alkyl group or a partly or fully deuterated, branched or linear alkyl group.

The invention accordingly further provides an organic electroluminescent device as described above or described as preferred, characterized in that the light-emitting layer, as well as the host materials 1 and 2, comprises at least one phosphorescent emitter conforming to the formula (III) as described above.

In emitters of the formula (III), n is preferably 1 and m is preferably 2.

In emitters of the formula (III), preferably one X is selected from N and the other X are CR.

In emitters of the formula (III), at least one R is preferably different from H.

In emitters of the formula (III), preferably two R are different from H and have one of the other definitions given above for the emitters of the formula (III).

Preferred phosphorescent emitters according to the present invention conform to the formulae (Ia), (IIa) and (IIIa)

where the symbols and indices for these formulae (Ia), (IIa) and (IIIa) are defined as follows:

R¹ is H or D, R² is H, D, or a branched or linear alkyl group having 1 to 10 carbon atoms or a partly or fully deuterated branched or linear alkyl group having 1 to 10 carbon atoms or a cycloalkyl group which has 4 to 10 carbon atoms and may be partly or fully substituted by deuterium.

Preferred phosphorescent emitters according to the present invention conform to the formulae (IVa), (Va) and (VIa)

where the symbols and indices for these formulae (IVa), (Va) and (VIa) are defined as follows:

R¹ is H or D, R² is H, D, F or a branched or linear alkyl group having 1 to 10 carbon atoms or a partly or fully deuterated branched or linear alkyl group having 1 to 10 carbon atoms or a cycloalkyl group which has 4 to 10 carbon atoms and may be partly or fully substituted by deuterium.

Preferred examples of phosphorescent emitters are listed in table 6 below.

TABLE 6

Preferred examples of phosphorescent polypodal emitters are listed in table 7 below.

TABLE 7 CAS-1269508-30-6 CAS-1989601-68-4 CAS-1989602-19-8 CAS-1989602-70-1 CAS-1215692-34-4 CAS-1989601-69-5 CAS-1989602-20-1 CAS-1989602-71-2 CAS-1370364-40-1 CAS-1989601-70-8 CAS-1989602-21-2 CAS-1989602-72-3 CAS-1370364-42-3 CAS-1989601-71-9 CAS-1989602-22-3 CAS-1989602-73-4 CAS-1989600-74-9 CAS-1989601-72-0 CAS-1989602-23-4 CAS-1989602-74-5 CAS-1989600-75-0 CAS-1989601-73-1 CAS-1989602-24-5 CAS-1989602-75-6 CAS-1989600-77-2 CAS-1989601-74-2 CAS-1989602-25-6 CAS-1989602-76-7 CAS-1989600-78-3 CAS-1989601-75-3 CAS-1989602-26-7 CAS-1989602-77-8 CAS-1989600-79-4 CAS-1989601-76-4 CAS-1989602-27-8 CAS-1989602-78-9 CAS-1989600-82-9 CAS-1989601-77-5 CAS-1989602-28-9 CAS-1989602-79-0 CAS-1989600-83-0 CAS-1989601-78-6 CAS-1989602-29-0 CAS-1989602-80-3 CAS-1989600-84-1 CAS-1989601-79-7 CAS-1989602-30-3 CAS-1989602-82-5 CAS-1989600-85-2 CAS-1989601-80-0 CAS-1989602-31-4 CAS-1989602-84-7 CAS-1989600-86-3 CAS-1989601-81-1 CAS-1989602-32-5 CAS-1989602-85-8 CAS-1989600-87-4 CAS-1989601-82-2 CAS-1989602-33-6 CAS-1989602-86-9 CAS-1989600-88-5 CAS-1989601-83-3 CAS-1989602-34-7 CAS-1989602-87-0 CAS-1989600-89-6 CAS-1989601-84-4 CAS-1989602-35-8 CAS-1989602-88-1 CAS-1989601-11-7 CAS-1989601-85-5 CAS-1989602-36-9 CAS-1989604-00-3 CAS-1989601-23-1 CAS-1989601-86-6 CAS-1989602-37-0 CAS-1989604-01-4 CAS-1989601-26-4 CAS-1989601-87-7 CAS-1989602-38-1 CAS-1989604-02-5 CAS-1989601-28-6 CAS-1989601-88-8 CAS-1989602-39-2 CAS-1989604-03-6 CAS-1989601-29-7 CAS-1989601-89-9 CAS-1989602-40-5 CAS-1989604-04-7 CAS-1989601-33-3 CAS-1989601-90-2 CAS-1989602-41-6 CAS-1989604-05-8 CAS-1989601-40-2 CAS-1989601-91-3 CAS-1989602-42-7 CAS-1989604-06-9 CAS-1989601-41-3 CAS-1989601-92-4 CAS-1989602-43-8 CAS-1989604-07-0 CAS-1989601-42-4 CAS-1989601-93-5 CAS-1989602-44-9 CAS-1989604-08-1 CAS-1989601-43-5 CAS-1989601-94-6 CAS-1989602-45-0 CAS-1989604-09-2 CAS-1989601-44-6 CAS-1989601-95-7 CAS-1989602-46-1 CAS-1989604-10-5 CAS-1989601-45-7 CAS-1989601-96-8 CAS-1989602-47-2 CAS-1989604-11-6 CAS-1989601-46-8 CAS-1989601-97-9 CAS-1989602-48-3 CAS-1989604-13-8 CAS-1989601-47-9 CAS-1989601-98-0 CAS-1989602-49-4 CAS-1989604-14-9 CAS-1989601-48-0 CAS-1989601-99-1 CAS-1989602-50-7 CAS-1989604-15-0 CAS-1989601-49-1 CAS-1989602-00-7 CAS-1989602-51-8 CAS-1989604-16-1 CAS-1989601-50-4 CAS-1989602-01-8 CAS-1989602-52-9 CAS-1989604-17-2 CAS-1989601-51-5 CAS-1989602-02-9 CAS-1989602-53-0 CAS-1989604-18-3 CAS-1989601-52-6 CAS-1989602-03-0 CAS-1989602-54-1 CAS-1989604-19-4 CAS-1989601-53-7 CAS-1989602-04-1 CAS-1989602-55-2 CAS-1989604-20-7 CAS-1989601-54-8 CAS-1989602-05-2 CAS-1989602-56-3 CAS-1989604-21-8 CAS-1989601-55-9 CAS-1989602-06-3 CAS-1989602-57-4 CAS-1989604-22-9 CAS-1989601-56-0 CAS-1989602-07-4 CAS-1989602-58-5 CAS-1989604-23-0 CAS-1989601-57-1 CAS-1989602-08-5 CAS-1989602-59-6 CAS-1989604-24-1 CAS-1989601-58-2 CAS-1989602-09-6 CAS-1989602-60-9 CAS-1989604-25-2 CAS-1989601-59-3 CAS-1989602-10-9 CAS-1989602-61-0 CAS-1989604-26-3 CAS-1989601-60-6 CAS-1989602-11-0 CAS-1989602-62-1 CAS-1989604-27-4 CAS-1989601-61-7 CAS-1989602-12-1 CAS-1989602-63-2 CAS-1989604-28-5 CAS-1989601-62-8 CAS-1989602-13-2 CAS-1989602-64-3 CAS-1989604-29-6 CAS-1989601-63-9 CAS-1989602-14-3 CAS-1989602-65-4 CAS-1989604-30-9 CAS-1989601-64-0 CAS-1989602-15-4 CAS-1989602-66-5 CAS-1989604-31-0 CAS-1989601-65-1 CAS-1989602-16-5 CAS-1989602-67-6 CAS-1989604-32-1 CAS-1989601-66-2 CAS-1989602-17-6 CAS-1989602-68-7 CAS-1989604-33-2 CAS-1989601-67-3 CAS-1989602-18-7 CAS-1989602-69-8 CAS-1989604-34-3 CAS-1989604-35-4 CAS-1989604-88-7 CAS-1989605-52-8 CAS-1989606-07-6 CAS-1989604-36-5 CAS-1989604-89-8 CAS-1989605-53-9 CAS-1989606-08-7 CAS-1989604-37-6 CAS-1989604-90-1 CAS-1989605-54-0 CAS-1989606-09-8 CAS-1989604-38-7 CAS-1989604-92-3 CAS-1989605-55-1 CAS-1989606-10-1 CAS-1989604-39-8 CAS-1989604-93-4 CAS-1989605-56-2 CAS-1989606-11-2 CAS-1989604-40-1 CAS-1989604-94-5 CAS-1989605-57-3 CAS-1989606-12-3 CAS-1989604-41-2 CAS-1989604-95-6 CAS-1989605-58-4 CAS-1989606-13-4 CAS-1989604-42-3 CAS-1989604-96-7 CAS-1989605-59-5 CAS-1989606-14-5 CAS-1989604-43-4 CAS-1989604-97-8 CAS-1989605-61-9 CAS-1989606-15-6 CAS-1989604-45-6 CAS-1989605-09-5 CAS-1989605-62-0 CAS-1989606-16-7 CAS-1989604-46-7 CAS-1989605-10-8 CAS-1989605-63-1 CAS-1989606-17-8 CAS-1989604-47-8 CAS-1989605-11-9 CAS-1989605-64-2 CAS-1989606-18-9 CAS-1989604-48-9 CAS-1989605-13-1 CAS-1989605-65-3 CAS-1989606-19-0 CAS-1989604-49-0 CAS-1989605-14-2 CAS-1989605-66-4 CAS-1989606-20-3 CAS-1989604-50-3 CAS-1989605-15-3 CAS-1989605-67-5 CAS-1989606-21-4 CAS-1989604-52-5 CAS-1989605-16-4 CAS-1989605-68-6 CAS-1989606-22-5 CAS-1989604-53-6 CAS-1989605-17-5 CAS-1989605-69-7 CAS-1989606-23-6 CAS-1989604-54-7 CAS-1989605-18-6 CAS-1989605-70-0 CAS-1989606-24-7 CAS-1989604-55-8 CAS-1989605-19-7 CAS-1989605-71-1 CAS-1989606-26-9 CAS-1989604-56-9 CAS-1989605-20-0 CAS-1989605-72-2 CAS-1989606-27-0 CAS-1989604-57-0 CAS-1989605-21-1 CAS-1989605-73-3 CAS-1989606-28-1 CAS-1989604-58-1 CAS-1989605-22-2 CAS-1989605-74-4 CAS-1989606-29-2 CAS-1989604-59-2 CAS-1989605-23-3 CAS-1989605-75-5 CAS-1989606-30-5 CAS-1989604-60-5 CAS-1989605-24-4 CAS-1989605-76-6 CAS-1989606-31-6 CAS-1989604-61-6 CAS-1989605-25-5 CAS-1989605-77-7 CAS-1989606-32-7 CAS-1989604-62-7 CAS-1989605-26-6 CAS-1989605-78-8 CAS-1989606-33-8 CAS-1989604-63-8 CAS-1989605-27-7 CAS-1989605-79-9 CAS-1989606-34-9 CAS-1989604-64-9 CAS-1989605-28-8 CAS-1989605-81-3 CAS-1989606-35-0 CAS-1989604-65-0 CAS-1989605-29-9 CAS-1989605-82-4 CAS-1989606-36-1 CAS-1989604-66-1 CAS-1989605-30-2 CAS-1989605-83-5 CAS-1989606-37-2 CAS-1989604-67-2 CAS-1989605-31-3 CAS-1989605-84-6 CAS-1989606-38-3 CAS-1989604-68-3 CAS-1989605-32-4 CAS-1989605-85-7 CAS-1989606-39-4 CAS-1989604-69-4 CAS-1989605-33-5 CAS-1989605-86-8 CAS-1989606-40-7 CAS-1989604-70-7 CAS-1989605-34-6 CAS-1989605-87-9 CAS-1989606-41-8 CAS-1989604-71-8 CAS-1989605-35-7 CAS-1989605-88-0 CAS-1989606-42-9 CAS-1989604-72-9 CAS-1989605-36-8 CAS-1989605-89-1 CAS-1989606-43-0 CAS-1989604-73-0 CAS-1989605-37-9 CAS-1989605-90-4 CAS-1989606-44-1 CAS-1989604-74-1 CAS-1989605-38-0 CAS-1989605-91-5 CAS-1989606-45-2 CAS-1989604-75-2 CAS-1989605-39-1 CAS-1989605-92-6 CAS-1989606-46-3 CAS-1989604-76-3 CAS-1989605-40-4 CAS-1989605-93-7 CAS-1989606-48-5 CAS-1989604-77-4 CAS-1989605-41-5 CAS-1989605-94-8 CAS-1989606-49-6 CAS-1989604-78-5 CAS-1989605-42-6 CAS-1989605-95-9 CAS-1989606-53-2 CAS-1989604-79-6 CAS-1989605-43-7 CAS-1989605-96-0 CAS-1989606-55-4 CAS-1989604-80-9 CAS-1989605-44-8 CAS-1989605-97-1 CAS-1989606-56-5 CAS-1989604-81-0 CAS-1989605-45-9 CAS-1989605-98-2 CAS-1989606-61-2 CAS-1989604-82-1 CAS-1989605-46-0 CAS-1989605-99-3 CAS-1989606-62-3 CAS-1989604-83-2 CAS-1989605-47-1 CAS-1989606-00-9 CAS-1989606-63-4 CAS-1989604-84-3 CAS-1989605-48-2 CAS-1989606-01-0 CAS-1989606-67-8 CAS-1989604-85-4 CAS-1989605-49-3 CAS-1989606-04-3 CAS-1989606-69-0 CAS-1989604-86-5 CAS-1989605-50-6 CAS-1989606-05-4 CAS-1989606-70-3 CAS-1989604-87-6 CAS-1989605-51-7 CAS-1989606-06-5 CAS-1989606-74-7 CAS-1989658-39-0 CAS-2088184-56-7 CAS-2088185-07-1 CAS-2088185-66-2 CAS-1989658-41-4 CAS-2088184-57-8 CAS-2088185-08-2 CAS-2088185-67-3 CAS-1989658-43-6 CAS-2088184-58-9 CAS-2088185-09-3 CAS-2088185-68-4 CAS-1989658-47-0 CAS-2088184-59-0 CAS-2088185-10-6 CAS-2088185-69-5 CAS-1989658-49-2 CAS-2088184-60-3 CAS-2088185-11-7 CAS-2088185-70-8 CAS-2088184-07-8 CAS-2088184-61-4 CAS-2088185-12-8 CAS-2088185-71-9 CAS-2088184-08-9 CAS-2088184-62-5 CAS-2088185-13-9 CAS-2088185-72-0 CAS-2088184-09-0 CAS-2088184-63-6 CAS-2088185-14-0 CAS-2088185-73-1 CAS-2088184-10-3 CAS-2088184-64-7 CAS-2088185-15-1 CAS-2088185-74-2 CAS-2088184-11-4 CAS-2088184-65-8 CAS-2088185-16-2 CAS-2088185-75-3 CAS-2088184-13-6 CAS-2088184-66-9 CAS-2088185-17-3 CAS-2088185-76-4 CAS-2088184-14-7 CAS-2088184-67-0 CAS-2088185-18-4 CAS-2088185-77-5 CAS-2088184-15-8 CAS-2088184-68-1 CAS-2088185-19-5 CAS-2088185-78-6 CAS-2088184-16-9 CAS-2088184-69-2 CAS-2088185-20-8 CAS-2088185-79-7 CAS-2088184-17-0 CAS-2088184-70-5 CAS-2088185-21-9 CAS-2088185-80-0 CAS-2088184-18-1 CAS-2088184-71-6 CAS-2088185-22-0 CAS-2088185-81-1 CAS-2088184-19-2 CAS-2088184-72-7 CAS-2088185-23-1 CAS-2088185-82-2 CAS-2088184-20-5 CAS-2088184-73-8 CAS-2088185-32-2 CAS-2088185-83-3 CAS-2088184-21-6 CAS-2088184-74-9 CAS-2088185-33-3 CAS-2088185-84-4 CAS-2088184-22-7 CAS-2088184-75-0 CAS-2088185-34-4 CAS-2088185-85-5 CAS-2088184-23-8 CAS-2088184-76-1 CAS-2088185-35-5 CAS-2088185-86-6 CAS-2088184-24-9 CAS-2088184-77-2 CAS-2088185-36-6 CAS-2088185-87-7 CAS-2088184-25-0 CAS-2088184-78-3 CAS-2088185-37-7 CAS-2088185-88-8 CAS-2088184-26-1 CAS-2088184-79-4 CAS-2088185-38-8 CAS-2088185-89-9 CAS-2088184-27-2 CAS-2088184-80-7 CAS-2088185-39-9 CAS-2088185-90-2 CAS-2088184-28-3 CAS-2088184-81-8 CAS-2088185-40-2 CAS-2088185-91-3 CAS-2088184-29-4 CAS-2088184-82-9 CAS-2088185-41-3 CAS-2088185-92-4 CAS-2088184-30-7 CAS-2088184-83-0 CAS-2088185-42-4 CAS-2088185-93-5 CAS-2088184-32-9 CAS-2088184-84-1 CAS-2088185-43-5 CAS-2088185-94-6 CAS-2088184-34-1 CAS-2088184-85-2 CAS-2088185-44-6 CAS-2088185-95-7 CAS-2088184-35-2 CAS-2088184-86-3 CAS-2088185-45-7 CAS-2088185-96-8 CAS-2088184-36-3 CAS-2088184-87-4 CAS-2088185-46-8 CAS-2088185-97-9 CAS-2088184-37-4 CAS-2088184-88-5 CAS-2088185-47-9 CAS-2088185-98-0 CAS-2088184-38-5 CAS-2088184-89-6 CAS-2088185-48-0 CAS-2088185-99-1 CAS-2088184-39-6 CAS-2088184-90-9 CAS-2088185-49-1 CAS-2088186-00-7 CAS-2088184-40-9 CAS-2088184-91-0 CAS-2088185-50-4 CAS-2088186-01-8 CAS-2088184-41-0 CAS-2088184-92-1 CAS-2088185-51-5 CAS-2088186-02-9 CAS-2088184-42-1 CAS-2088184-93-2 CAS-2088185-52-6 CAS-2088195-88-2 CAS-2088184-43-2 CAS-2088184-94-3 CAS-2088185-53-7 CAS-2088195-89-3 CAS-2088184-44-3 CAS-2088184-95-4 CAS-2088185-54-8 CAS-2088195-90-6 CAS-2088184-45-4 CAS-2088184-96-5 CAS-2088185-55-9 CAS-2088195-91-7 CAS-2088184-46-5 CAS-2088184-97-6 CAS-2088185-56-0 CAS-861806-70-4 CAS-2088184-47-6 CAS-2088184-98-7 CAS-2088185-57-1 CAS-1269508-30-6 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In the mixtures of the invention or in the light-emitting layer of the device of the invention, any mixture M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13, M14, M15, M16, M17, M18, M19, M20, M21, M22, M23, M24, M25, M26, M27, M28, M29, M30, M31, M32, M33, M34, M35, M36, M37, M38, M39, M40, M41, M42, M43, M44, M45, M46, M47, M48, M49, M50, M51, M52, M53, M54, M55, M56, M57, M58, M59, M60, M61, M62, M63, M64, M65, M66, M67, M68, M69, M70, M71, M72, M73, M74, M75, M76, M77, M78, M79, M80, M81, M82, M83, M84, M85, M86, M87, M88, M89, M90, M91, M92, M93, M94, M95, M96, M97, M98, M99, M100, M101, M102, M103, M104, M105, M106, M107, M108, M109, M110, M111, M112, M113, M114, M115, M116, M117, M118, M119, M120, M121, M122, M123, M124, M125, M126, M127, M128, M129, M130, M131, M132, M133, M134, M135, M136, M137, M138, M139, M140, M141, M142, M143, M144, M145, M146, M147, M148, M149, M150, M151, M152, M153, M154, M155, M156, M157, M158, M159, M160, M161, M162, M163, M164, M165, M166, M167, M168, M169, M170, M171, M172, M173, M174, M175, M176, M177, M178, M179, M180, M181, M182, M183, M184, M185, M186, M187, M188, M189, M190, M191, M192, M193, M194, M195, M196, M197, M198, M199, M200, M201, M202, M203, M204, M205, M206, M207, M208, M209, M210, M211, M212, M213, M214, M215, M216, M217, M218, M219, M220, M221, M222, M223, M224, M225, M226, M227, M228, M229, M230, M231, M232, M233, M234, M235, M236, M237, M238, M239, M240, M241, M242, M243, M244, M245, M246, M247, M248, M249, M250, M251, M252, M253, M254, M255, M256, M257, M258, M259, M260, M261, M262, M263, M264, M265, M266, M267, M268, M269, M270, M271, M272, M273, M274, M275, M276, M277, M278, M279, M280, M281, M282, M283, M284, M285, M286, M287, M288, M289, M290, M291, M292, M293, M294, M295, M296, M297, M298, M299, M300, M301, M302, M303, M304, M305, M306, M307, M308, M309, M310, M311, M312, M313, M314, M315, M316, M317, M318, M319, M320, M321, M322, M323, M324, M325, M326, M327, M328, M329, M330, M331, M332, M333, M334, M335, M336, M337, M338, M339, M340, M341, M342, M343, M344, M345, M346, M347, M348, M349, M350, M351, M352, M353, M354, M355, M356, M357, M358, M359, M360, M361, M362, M363, M364, M365, M366, M367, M368, M369, M370, M371, M372, M373, M374, M375, M376, M377, M378, M379, M380, M381, M382, M383, M384, M385, M386, M387, M388, M389, M390, M391, M392, M393, M394, M395, M396, M397, M398, M399, M400, M401, M402, M403, M404, M405, M406, M407, M408, M409, M410, M411, M412, M413, M414, M415, M416, M417, M418, M419, M420, M421, M422, M423, M424, M425, M426, M427, M428, M429, M430, M431, M432, M433, M434, M435, M436, M437, M438, M439, M440, M441, M442, M443, M444, M445, M446, M447, M448, M449, M450, M451, M452, M453, M454, M455, M456, M457, M458, M459, M460, M461, M462, M463, M464, M465, M466, M467, M468, M469, M470, M471, M472, M473, M474, M475, M476, M477, M478, M479, M480, M481, M482, M483, M484, M485, M486, M487, M488, M489, M490, M491, M492, M493, M494, M495, M496, M497, M498, M499, M500, M501, M502, M503, M504, M505, M506, M507, M508, M509, M510, M511, M512, M513, M514, M515, M516, M517, M518, M519, M520, M521, M522, M523, M524, M525, M526, M527, M528, M529, M530, M531, M532, M533, M534, M535, M536, M537, M538, M539, M540, M541, M542, M543, M544, M545, M546, M547, M548, M549, M550, M551, M552, M553, M554, M555, M556, M557, M558, M559, M560, M561, M562, M563, M564, M565, M566, M567, M568, M569, M570, M571, M572, M573, M574, M575, M576, M577, M578, M579, M580, M581, M582, M583, M584, M585, M586, M587, M588, M589, M590, M591, M592, M593, M594, M595, M596, M597, M598, M599, M600, M601, M602, M603, M604, M605, M606, M607, M608, M609, M610, M611, M612, M613, M614, M615, M616, M617, M618, M619, M620, M621, M622, M623, M624, M625, M626, M627, M628, M629, M630, M631, M632, M633, M634, M635, M636, M637, M638, M639, M640, M641, M642, M643, M644, M645, M646, M647, M648, M649, M650, M651, M652, M653, M654, M655, M656, M657, M658, M659, M660, M661, M662, M663, M664, M665, M666, M667, M668, M669, M670, M671, M672, M673, M674, M675, M676, M677, M678, M679, M680, M681, M682, M683, M684, M685, M686, M687, M688, M689, M690, M691, M692, M693, M694, M695, M696, M697, M698, M699, M700, M701, M702, M703, M704, M705, M706, M707, M708, M709, M710, M711, M712, M713, M714, M715, M716, M717, M718, M719, M720, M721, M722, M723, M724, M725, M726, M727, M728, M729, M730, M731, M732, M733, M734, M735, M736, M737, M738, M739, M740, M741, M742, M743, M744, M745, M746, M747, M748, M749, M750, M751, M752, M753, M754, M755, M756, M757, M758, M759, M760, M761, M762, M763, M764, M765, M766, M767, M768, M769, M770, M771, M772, M773, M774, M775, M776, M777, M778, M779, M780, M781, M782, M783, M784, M785, M786, M787, M788, M789, M790, M791, M792, M793, M794, M795, M796, M797, M798, M799, M800, M801, M802, M803, M804, M805, M806, M807, M808, M809, M810, M811, M812, M813, M814, M815, M816, M817, M818, M819, M820, M821, M822, M823, M824, M825, M826, M827, M828, M829, M830, M831, M832, M833, M834, M835, M836, M837, M838, M839, M840, M841, M842, M843, M844, M845, M846, M847, M848, M849, M850, M851, M852, M853, M854, M855, M856, M857, M858, M859, M860, M861, M862, M863, M864, M865, M866, M867, M868, M869, M870, M871, M872, M873, M874, M875, M876, M877, M878, M879, M880, M881, M882, M883, M884, M885, M886, M887, M888, M889, M890, M891, M892, M893, M894, M895, M896, M897, M898, M899, M900, M901, M902, M903, M904, M905, M906, M907, M908, M909, M910, M911, M912, M913, M914, M915, M916, M917, M918, M919, M920, M921, M922, M923, M924, M925, M926, M927, M928, M929, M930, M931, M932, M933, M934, M935, M936, M937, M938, M939, M940, M941, M942, M943, M944, M945, M946, M947, M948, M949, M950, M951, M952, M953, M954, M955, M956, M957, M958, M959, M960, M961, M962, M963, M964, M965, M966, M967, M968, M969, M970, M971, M972, M973, M974, M975, M976, M977, M978, M979, M980, M981, M982, M983, M984, M985, M986, M987, M988, M989, M990, M991, M992, M993, M994, M995, M996, M997, M998, M999, M1000, M1001, M1002, M1003, M1004, M1005, M1006, M1007, M1008 is preferably combined with a compound of the formula (III) or a compound of the formulae (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or a compound from table 6 or 7.

The light-emitting layer in the organic electroluminescent device of the invention, comprising at least one phosphorescent emitter, is preferably an infrared-emitting or yellow-, orange-, red-, green-, blue- or ultraviolet-emitting layer, more preferably a yellow- or green-emitting layer and most preferably a green-emitting layer.

A yellow-emitting layer is understood here to mean a layer having a photoluminescence maximum within the range from 540 to 570 nm. An orange-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 570 to 600 nm. A red-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 600 to 750 nm. A green-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 490 to 540 nm. A blue-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 440 to 490 nm. The photoluminescence maximum of the layer is determined here by measuring the photoluminescence spectrum of the layer having a layer thickness of 50 nm at room temperature, said layer having the inventive combination of the host materials of the formulae (1) and (2) and the appropriate emitter.

The photoluminescence spectrum of the layer is recorded, for example, with a commercial photoluminescence spectrometer.

The photoluminescence spectrum of the emitter chosen is generally measured in oxygen-free solution, 10⁻⁵ molar, at room temperature, a suitable solvent being any in which the chosen emitter dissolves in the concentration mentioned. Particularly suitable solvents are typically toluene or 2-methyl-THF, but also dichloromethane. Measurement is effected with a commercial photoluminescence spectrometer. The triplet energy T1 in eV is determined from the photoluminescence spectra of the emitters. Firstly, the peak maximum PImax. (in nm) of the photoluminescence spectrum is determined. The peak maximum PImax. (in nm) is then converted to eV by: E(T1 in eV)=1240/E(T1 in nm)=1240/PLmax. (in nm).

Preferred phosphorescent emitters are accordingly infrared emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably −1.9 eV to −1.0 eV.

Preferred phosphorescent emitters are accordingly red emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably −2.1 eV to −1.9 eV.

Preferred phosphorescent emitters are accordingly yellow emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably −2.3 eV to −2.1 eV.

Preferred phosphorescent emitters are accordingly green emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably ˜2.5 eV to ˜2.3 eV.

Preferred phosphorescent emitters are accordingly blue emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably ˜3.1 eV to ˜2.5 eV.

Preferred phosphorescent emitters are accordingly ultraviolet emitters of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably ˜4.0 eV to ˜3.1 eV.

Particularly preferred phosphorescent emitters are accordingly green or yellow emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7 as described above.

Very particularly preferred phosphorescent emitters are accordingly green emitters, preferably of the formula (III), (Ia), (IIa), (IIIa), (IVa), (Va), (VIa) or from table 6 or 7, the triplet energy T₁ of which is preferably ˜2.5 eV to ˜2.3 eV.

Most preferably, green emitters, preferably of the formula (III) or from table 6 or 7, as described above, are selected for the composition of the invention or emitting layer of the invention.

It is also possible for fluorescent emitters to be present in the light-emitting layer of the device of the invention.

Preferred fluorescent emitters are selected from the class of the arylamines. An arylamine or an aromatic amine in the context of this invention is understood to mean a compound containing three substituted or unsubstituted aromatic or heteroaromatic ring systems bonded directly to the nitrogen. Preferably, at least one of these aromatic or heteroaromatic ring systems is a fused ring system, more preferably having at least 14 aromatic ring atoms. Preferred examples of these are aromatic anthraceneamines, aromatic anthracenediamines, aromatic pyreneamines, aromatic pyrenediamines, aromatic chryseneamines or aromatic chrysenediamines. An aromatic anthraceneamine is understood to mean a compound in which a diarylamino group is bonded directly to an anthracene group, preferably in the 9 position. An aromatic anthracenediamine is understood to mean a compound in which two diarylamino groups are bonded directly to an anthracene group, preferably in the 9,10 position. Aromatic pyreneamines, pyrenediamines, chryseneamines and chrysenediamines are defined analogously, where the diarylamino groups are bonded to the pyrene preferably in the 1 position or 1,6 position. Further preferred fluorescent emitters are indenofluoreneamines or -diamines, for example according to WO 2006/108497 or WO 2006/122630, benzoindenofluoreneamines or -diamines, for example according to WO 2008/006449, and dibenzoindenofluoreneamines or -diamines, for example according to WO 2007/140847, and the indenofluorene derivatives having fused aryl groups disclosed in WO 2010/012328.

In a further preferred embodiment of the invention, the at least one light-emitting layer of the organic electroluminescent device, as well as the host materials 1 and 2, as described above or described as preferred, may comprise further host materials or matrix materials, called mixed matrix systems. The mixed matrix systems preferably comprise three or four different matrix materials, more preferably three different matrix materials (in other words, one further matrix component in addition to the host materials 1 and 2, as described above). Particularly suitable matrix materials which can be used in combination as matrix component in a mixed matrix system are selected from wide-band gap materials, bipolar host materials, electron transport materials (ETM) and hole transport materials (HTM).

A wide-band gap material is understood herein to mean a material within the scope of the disclosure of U.S. Pat. No. 7,294,849 which is characterized by a band gap of at least 3.5 eV, the band gap being understood to mean the gap between the HOMO and LUMO energy of a material.

In one embodiment of the present invention, the mixture does not comprise any further constituents, i.e. functional materials, aside from the constituents of electron-transporting host material of the formula (1) and hole-transporting host material of the formula (2). These are material mixtures that are used as such for production of the light-emitting layer. These mixtures are also referred to as premix systems that are used as the sole material source in the vapour deposition of the host materials for the light-emitting layer and have a constant mixing ratio in the vapour deposition. In this way, it is possible in a simple and rapid manner to achieve the vapour deposition of a layer with homogeneous distribution of the components without the need for precise actuation of a multitude of material sources.

In an alternative embodiment of the present invention, the mixture also comprises the phosphorescent emitter, as described above, in addition to the constituents of electron-transporting host material of the formula (1) and hole-transporting host material of the formula (2). In the case of a suitable mixing ratio in the vapour deposition, this mixture may also be used as the sole material source, as described above.

The components or constituents of the light-emitting layer of the device of the invention may thus be processed by vapour deposition or from solution. The material combination of host materials 1 and 2, as described above or described as preferred, optionally with the phosphorescent emitter, as described above or described as preferred, are provided for the purpose in a formulation containing at least one solvent. These formulations may, for example, be solutions, dispersions or emulsions. For this purpose, it may be preferable to use mixtures of two or more solvents.

The present invention therefore further provides a formulation comprising an inventive mixture of host materials 1 and 2, as described above, optionally in combination with a phosphorescent emitter, as described above or described as preferred, and at least one solvent.

Suitable and preferred solvents are, for example, toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene, tetralin, veratrole, THF, methyl-THF, THP, chlorobenzene, dioxane, phenoxytoluene, especially 3-phenoxytoluene, (−)-fenchone, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, 1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol, 2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole, 3,5-dimethylanisole, acetophenone, α-terpineol, benzothiazole, butyl benzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene, decalin, dodecylbenzene, ethyl benzoate, indane, methyl benzoate, NMP, p-cymene, phenetole, 1,4-diisopropylbenzene, dibenzyl ether, diethylene glycol butyl methyl ether, triethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene, pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, 1,1-bis(3,4-dimethylphenyl)ethane, hexamethylindane or mixtures of these solvents.

The formulation here may also comprise at least one further organic or inorganic compound which is likewise used in the light-emitting layer of the device of the invention, especially a further emitting compound and/or a further matrix material.

The light-emitting layer in the device of the invention, according to the preferred embodiments and the emitting compound, contains preferably between 99.9% and 1% by volume, further preferably between 99% and 10% by volume, especially preferably between 98% and 60% by volume, very especially preferably between 97% and 80% by volume, of matrix material composed of at least one compound of the formula (1) and at least one compound of the formula (2) according to the preferred embodiments, based on the overall composition of emitter and matrix material. Correspondingly, the light-emitting layer in the device of the invention preferably contains between 0.1% and 99% by volume, further preferably between 1% and 90% by volume, more preferably between 2% and 40% by volume, most preferably between 3% and 20% by volume, of the emitter based on the overall composition of the light-emitting layer composed of emitter and matrix material. If the compounds are processed from solution, preference is given to using the corresponding amounts in % by weight rather than the above-specified amounts in % by volume.

The light-emitting layer in the device of the invention, according to the preferred embodiments and the emitting compound, preferably contains the matrix material of the formula (1) and the matrix material of the formula (2) in a percentage by volume ratio between 3:1 and 1:3, preferably between 1:2.5 and 1:1, more preferably between 1:2 and 1:1. If the compounds are processed from solution, preference is given to using the corresponding ratio in % by weight rather than the above-specified ratio in % by volume.

The sequence of layers in the organic electroluminescent device of the invention is preferably as follows:

anode/hole injection layer/hole transport layer/emitting layer/electron transport layer/electron injection layer/cathode.

This sequence of the layers is a preferred sequence.

At the same time, it should be pointed out again that not all the layers mentioned need be present and/or that further layers may additionally be present.

The organic electroluminescent device of the invention may contain two or more emitting layers. At least one of the emitting layers is the light-emitting layer of the invention containing at least one compound of the formula (1) as host material 1 and at least one compound of the formula (2) as host material 2 as described above. More preferably, these emission layers in this case have several emission maxima between 380 nm and 750 nm overall, such that the overall result is white emission; in other words, various emitting compounds which may fluoresce or phosphoresce and which emit blue or yellow or orange or red light are used in the emitting layers. Especially preferred are three-layer systems, i.e. systems having three emitting layers, where the three layers show blue, green and orange or red emission (for the basic construction see, for example, WO 2005/011013). It should be noted that, for the production of white light, rather than a plurality of colour-emitting emitter compounds, an emitter compound used individually which emits over a broad wavelength range may also be suitable.

Suitable charge transport materials as usable in the hole injection or hole transport layer or electron blocker layer or in the electron transport layer of the organic electroluminescent device of the invention are, for example, the compounds disclosed in Y. Shirota et al., Chem. Rev. 2007, 107(4), 953-1010, or other materials as used in these layers according to the prior art.

Materials used for the electron transport layer may be any materials as used according to the prior art as electron transport materials in the electron transport layer. Especially suitable are aluminium complexes, for example Alq3, zirconium complexes, for example Zrq4, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives, quinoline derivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphole derivatives and phosphine oxide derivatives. Further suitable materials are derivatives of the abovementioned compounds as disclosed in JP 2000/053957, WO 2003/060956, WO 2004/028217, WO 2004/080975 and WO 2010/072300.

Preferred hole transport materials are especially materials which can be used in a hole transport, hole injection or electron blocker layer, such as indenofluoreneamine derivatives (for example according to WO 06/122630 or WO 06/100896), the amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (for example according to WO 01/049806), amine derivatives having fused aromatic systems (for example according to U.S. Pat. No. 5,061,569), the amine derivatives disclosed in WO 95/09147, monobenzoindenofluoreneamines (for example according to WO 08/006449), dibenzoindenofluoreneamines (for example according to WO 07/140847), spirobifluoreneamines (for example according to WO 2012/034627 or the as yet unpublished EP 12000929.5), fluoreneamines (for example according to WO 2014/015937, WO 2014/015938 and WO 2014/015935), spirodibenzopyranamines (for example according to WO 2013/083216) and dihydroacridine derivatives (for example WO 2012/150001).

Suitable cathodes of the device of the invention are metals having a low work function, metal alloys or multilayer structures composed of various metals, for example alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g. Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Additionally suitable are alloys composed of an alkali metal or alkaline earth metal and silver, for example an alloy composed of magnesium and silver. In the case of multilayer structures, in addition to the metals mentioned, it is also possible to use further metals having a relatively high work function, for example Ag or Al, in which case combinations of the metals such as Ca/Ag, Mg/Ag or Ba/Ag, for example, are generally used. It may also be preferable to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic semiconductor. Examples of useful materials for this purpose are alkali metal or alkaline earth metal fluorides, but also the corresponding oxides or carbonates (e.g. LiF, Li₂O, BaF₂, MgO, NaF, CsF, Cs₂CO₃, etc.). It is also possible to use lithium quinolinate (LiQ) for this purpose. The layer thickness of this layer is preferably between 0.5 and 5 nm.

Preferred anodes are materials having a high work function. Preferably, the anode has a work function of greater than 4.5 eV versus vacuum. Firstly, metals having a high redox potential are suitable for this purpose, for example Ag, Pt or Au. Secondly, metal/metal oxide electrodes (e.g. Al/Ni/NiO_(x), Al/PtO_(x)) may also be preferred. For some applications, at least one of the electrodes has to be transparent or partly transparent in order to enable either the irradiation of the organic material (organic solar cell) or the emission of light (OLED, O-LASER). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is further given to conductive doped organic materials, especially conductive doped polymers. In addition, the anode may also consist of two or more layers, for example of an inner layer of ITO and an outer layer of a metal oxide, preferably tungsten oxide, molybdenum oxide or vanadium oxide.

The organic electroluminescent device of the invention, in the course of production, is appropriately (according to the application) structured, contact-connected and finally sealed, since the lifetime of the devices of the invention is shortened in the presence of water and/or air.

The production of the device of the invention is not restricted here. It is possible that one or more organic layers, including the light-emitting layer, are coated by a sublimation method. In this case, the materials are applied by vapour deposition in vacuum sublimation systems at an initial pressure of less than 10⁻⁵ mbar, preferably less than 10⁻⁶ mbar. In this case, however, it is also possible that the initial pressure is even lower, for example less than 10⁻⁷ mbar.

The organic electroluminescent device of the invention is preferably characterized in that one or more layers are coated by the OVPD (organic vapour phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10⁻⁵ mbar and 1 bar. A special case of this method is the OVJP (organic vapour jet printing) method, in which the materials are applied directly by a nozzle and thus structured (for example, M. S. Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

The organic electroluminescent device of the invention is further preferably characterized in that one or more organic layers comprising the composition of the invention are produced from solution, for example by spin-coating, or by any printing method, for example screen printing, flexographic printing, nozzle printing or offset printing, but more preferably LITI (light-induced thermal imaging, thermal transfer printing) or inkjet printing. For this purpose, soluble host materials 1 and 2 and phosphorescent emitters are needed. Processing from solution has the advantage that, for example, the light-emitting layer can be applied in a very simple and inexpensive manner. This technique is especially suitable for the mass production of organic electroluminescent devices.

In addition, hybrid methods are possible, in which, for example, one or more layers are applied from solution and one or more further layers are applied by vapour deposition.

These methods are known in general terms to those skilled in the art and can be applied to organic electroluminescent devices.

The invention therefore further provides a process for producing the organic electroluminescent device of the invention as described above or described as preferred, characterized in that the light-emitting layer is applied by gas phase deposition, especially by a sublimation method and/or by an OVPD (organic vapour phase deposition) method and/or with the aid of a carrier gas sublimation, or from solution, especially by spin-coating or by a printing method.

In the case of production by means of gas phase deposition, there are in principle two ways in which the light-emitting layer of the invention can be applied or vapour-deposited onto any substrate or the prior layer. Firstly, the materials used can each be initially charged in a material source and ultimately evaporated from the different material sources (“co-evaporation”). Secondly, the various materials can be premixed (premix systems) and the mixture can be initially charged in a single material source from which it is ultimately evaporated (“premix evaporation”). In this way, it is possible in a simple and rapid manner to achieve the vapour deposition of the light-emitting layer with homogeneous distribution of the components without the need for precise actuation of a multitude of material sources.

The invention accordingly further provides a process for producing the device of the invention, characterized in that the at least one compound of the formula (1) as described above or described as preferred and the at least one compound of the formula (2) as described above or described as preferred are deposited from the gas phase successively or simultaneously from at least two material sources, optionally with the at least one phosphorescent emitter as described above or described as preferred, and form the light-emitting layer.

In a preferred embodiment of the present invention, the light-emitting layer is applied by means of gas phase deposition, wherein the constituents of the composition are premixed and evaporated from a single material source.

The invention accordingly further provides a process for producing the device of the invention, characterized in that the at least one compound of the formula (1) and the at least one compound of the formula (2) are deposited from the gas phase as a mixture, successively or simultaneously with the at least one phosphorescent emitter, and form the light-emitting layer.

The invention further provides a process for producing the device of the invention, as described above or described as preferred, characterized in that the at least one compound of the formula (1) and the at least one compound of the formula (2), as described above or described as preferred, are applied from solution together with the at least one phosphorescent emitter in order to form the light-emitting layer.

The devices of the invention feature the following surprising advantages over the prior art:

The use of the described material combination of host materials 1 and 2, as described above, especially leads to an increase in the lifetime of the devices.

As apparent in the example given hereinafter, it is possible to determine by comparison of the data for OLEDs with combinations from the prior art that the inventive combinations of matrix materials in the EML lead to devices having an increase in lifetime by about 20% to 70%, irrespective of the emitter concentration.

It should be pointed out that variations of the embodiments described in the present invention are covered by the scope of this invention. Any feature disclosed in the present invention may, unless this is explicitly ruled out, be exchanged for alternative features which serve the same purpose or an equivalent or similar purpose. Any feature disclosed in the present invention, unless stated otherwise, should therefore be considered as an example from a generic series or as an equivalent or similar feature.

All features of the present invention may be combined with one another in any manner, unless particular features and/or steps are mutually exclusive. This is especially true of preferred features of the present invention. Equally, features of non-essential combinations may be used separately (and not in combination).

The technical teaching disclosed with the present invention may be abstracted and combined with other examples.

The invention is illustrated in more detail by the examples which follow, without any intention of restricting it thereby.

General Methods:

In all quantum-chemical calculations, the Gaussian16 (Rev. B.01) software package is used. The neutral singlet ground state is optimized at the B3LYP/6-31G(d) level. HOMO and LUMO values are determined at the B3LYP/6-31G(d) level for the B3LYP/6-31G(d)-optimized ground state energy. Then TD-DFT singlet and triplet excitations (vertical excitations) are calculated by the same method (B3LYP/6-31G(d)) and with the optimized ground state geometry. The standard settings for SCF and gradient convergence are used.

From the energy calculation, the HOMO is obtained as the last orbital occupied by two electrons (alpha occ. eigenvalues) and LUMO as the first unoccupied orbital (alpha virt. eigenvalues) in Hartree units, where HEh and LEh represent the HOMO energy in Hartree units and the LUMO energy in Hartree units respectively. This is used to determine the HOMO and LUMO value in electron volts, calibrated by cyclic voltammetry measurements, as follows:

HOMOcorr=0.90603*HOMO−0.84836

LUMOcorr=0.99687*LUMO−0.72445

The triplet level T1 of a material is defined as the relative excitation energy (in eV) of the triplet state having the lowest energy which is found by the quantum-chemical energy calculation.

The singlet level S1 of a material is defined as the relative excitation energy (in eV) of the singlet state having the second-lowest energy which is found by the quantum-chemical energy calculation.

The energetically lowest singlet state is referred to as S0.

The method described herein is independent of the software package used and always gives the same results. Examples of frequently utilized programs for this purpose are “Gaussian09” (Gaussian Inc.) and Q-Chem 4.1 (Q-Chem, Inc.). In the present case, the energies are calculated using the software package “Gaussian16 (Rev. B.01)”.

EXAMPLE 1: PRODUCTION OF THE OLEDS

The examples which follow (see tables 8 to 10) present the use of the material combinations of the invention in OLEDs by comparison with material combinations from the prior art.

Pretreatment for examples V1 to V6 and E1a to E6f: Glass plates coated with structured ITO (indium tin oxide) of thickness 50 nm are treated prior to coating, first with an oxygen plasma, followed by an argon plasma. These plasma-treated glass plates form the substrates to which the OLEDs are applied.

The OLEDs basically have the following layer structure: substrate/hole injection layer (HIL)/hole transport layer (HTL)/electron blocker layer (EBL)/emission layer (EML)/optional hole blocker layer (HBL)/electron transport layer (ETL)/optional electron injection layer (EIL) and finally a cathode. The cathode is formed by an aluminium layer of thickness 100 nm. The exact structure of the OLEDs can be found in table 8. The materials required for production of the OLEDs, if they have not already been described before, are shown in table 10. The device data of the OLEDs are listed in table 9.

Examples V1 and V6 are comparative examples of the host materials E40 to E45 that are known from WO19007866 with a biscarbazole as hole-transporting host according to the prior art, for example WO19007866. Examples E1a to E6f show data for OLEDs of the invention.

All materials are applied by thermal vapour deposition in a vacuum chamber. In this case, the emission layer always consists of at least two matrix materials and an emitting dopant (emitter) which is added to the matrix material(s) in a particular proportion by volume by co-evaporation. Details given in such a form as E40:BCbz1:TE2 (32%:60%:8%) mean here that the material E40 is present in the layer in a proportion by volume of 32%, BCbz1 in a proportion of 60% and TE2 in a proportion of 8%.

Analogously, the electron transport layer may also consist of a mixture of two materials.

The OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectra and current-voltage-luminance characteristics (IUL characteristics) are measured. EQE and current efficiency SE (in cd/A) are calculated therefrom. SE is calculated assuming Lambertian emission characteristics.

The electroluminescence spectra are determined at a luminance of 1000 cd/m², and the CIE 1931 x and y colour coordinates are calculated therefrom. The parameter U10 in table 2 refers to the voltage which is required for a current density of 10 mA/cm². CE10 and EQE10 respectively denote the current efficiency and external quantum efficiency that are attained at 10 mA/cm².

The lifetime LT is defined as the time after which luminance, measured in cd/m² in forward direction, drops from the starting luminance to a certain proportion L1 in the course of operation with constant current density jo. A figure of L1=80% in table 9 means that the lifetime reported in the LT column corresponds to the time after which luminance in cd/m² falls to 80% of its starting value.

Use of Mixtures of the Invention in OLEDs

The material combinations of the invention are used in examples E1a-i, E2a-f, E3a-f, E4a-f, E5a-g, E6a-f as matrix material in the emission layer of green-phosphorescing OLEDs. As a comparison with the prior art, materials E40 to E45 with BCbz1 to BCbz3 are used in examples V1 to V6.

On comparison of the inventive examples with the corresponding comparative examples, it is clearly apparent that the inventive examples each show a distinct advantage in device lifetime, with otherwise comparable performance data of the OLEDs.

TABLE 8 Structure of the OLEDs HIL HTL EBL EML HBL ETL EIL Ex. thickness thickness thickness thickness thickness thickness thickness V1 SpMA1:PD1 SpMA1 SpMA2 E40:BCbz1:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1a SpMA1:PD1 SpMA1 SpMA2 E40:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1b SpMA1:PD1 SpMA1 SpMA2 E40:H7:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1c SpMA1:PD1 SpMA1 SpMA2 E40:H12:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1d SpMA1:PD1 SpMA1 SpMA2 E1:H13:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1e SpMA1:PD1 SpMA1 SpMA2 E3:H18:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1f SpMA1:PD1 SpMA1 SpMA2 E10:H16:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1g SpMA1:PD1 SpMA1 SpMA2 E14:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1h SpMA1:PD1 SpMA1 SpMA2 E29:H16:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E1i SpMA1:PD1 SpMA1 SpMA2 E34:H13:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm V2 SpMA1:PD1 SpMA1 SpMA2 E41:BCbz1:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2a SpMA1:PD1 SpMA1 SpMA2 E41:H5:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2b SpMA1:PD1 SpMA1 SpMA2 E41:H8:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2c SpMA1:PD1 SpMA1 SpMA2 E41:H10:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2d SpMA1:PD1 SpMA1 SpMA2 E6:H5:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2e SpMA1:PD1 SpMA1 SpMA2 E8:H17:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E2f SpMA1:PD1 SpMA1 SpMA2 E48:H17:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm V3 SpMA1:PD1 SpMA1 SpMA2 E42:BCbz2:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3a SpMA1:PD1 SpMA1 SpMA2 E42:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3b SpMA1:PD1 SpMA1 SpMA2 E28:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3c SpMA1:PD1 SpMA1 SpMA2 E26:H5:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3d SpMA1:PD1 SpMA1 SpMA2 E24:H7:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3e SpMA1:PD1 SpMA1 SpMA2 E33:H12:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E3f SpMA1:PD1 SpMA1 SpMA2 E46:H7:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm V4 SpMA1:PD1 SpMA1 SpMA2 E43:BCbz2:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4a SpMA1:PD1 SpMA1 SpMA2 E43:H5:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4b SpMA1:PD1 SpMA1 SpMA2 E4:H7:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4c SpMA1:PD1 SpMA1 SpMA2 E20:H8:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4d SpMA1:PD1 SpMA1 SpMA2 E19:H5:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4e SpMA1:PD1 SpMA1 SpMA2 E22:H3:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E4f SpMA1:PD1 SpMA1 SpMA2 E32:H18:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm V5 SpMA1:PD1 SpMA1 SpMA2 E44:BCbz3:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5a SpMA1:PD1 SpMA1 SpMA2 E44:H3:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5b SpMA1:PD1 SpMA1 SpMA2 E5:H14:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5c SpMA1:PD1 SpMA1 SpMA2 E14:H3:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5d SpMA1:PD1 SpMA1 SpMA2 E21:H8:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5e SpMA1:PD1 SpMA1 SpMA2 E16:H12:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5f SpMA1:PD1 SpMA1 SpMA2 E30:H3:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm E5g SpMA1:PD1 SpMA1 SpMA2 E47:H5:TE1 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (38%:50%:12%) 40 nm 5 nm (50%:50%) 30 nm V6 SpMA1:PD1 SpMA1 SpMA2 E45:BCbz3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6a SpMA1:PD1 SpMA1 SpMA2 E45:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6b SpMA1:PD1 SpMA1 SpMA2 E7:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6c SpMA1:PD1 SpMA1 SpMA2 E12:H7:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6d SpMA1:PD1 SpMA1 SpMA2 E18:H13:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6e SpMA1:PD1 SpMA1 SpMA2 E31:H5:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm E6f SpMA1:PD1 SpMA1 SpMA2 E36:H3:TE2 ST2 ST2:LiQ LiQ 1 nm (95%:5%) 20 nm 200 nm 20 nm (32%:60%:8%) 40 nm 5 nm (50%:50%) 30 nm

TABLE 9 Data of the OLEDs U10 EQE10 CIE x/y at j₀ L1 LT Ex. (V) (%) 1000 cd/m² (mA/cm²) (%) (h) V1 4.4 21.5 0.35/0.63 40 80 620 E1a 4.5 21.6 0.35/0.63 40 80 790 E1b 4.4 21.5 0.35/0.63 40 80 820 E1c 4.6 21.4 0.35/0.63 40 80 840 E1d 4.4 22.7 0.35/0.63 40 80 785 E1e 4.4 22.5 0.35/0.63 40 80 740 E1f 4.6 22.0 0.35/0.63 40 80 710 E1d 4.3 21.9 0.35/0.63 40 80 800 E1h 4.7 21.9 0.35/0.63 40 80 710 E1i 4.5 22.0 0.35/0.63 40 80 825 V2 4.4 23.7 0.35/0.63 40 80 510 E2a 4.5 22.2 0.35/0.63 40 80 665 E2b 4.6 22.9 0.35/0.63 40 80 740 E2c 4.4 22.6 0.35/0.63 40 80 575 E2d 4.6 21.7 0.35/0.63 40 80 800 E2e 4.6 22.1 0.35/0.63 40 80 640 E2f 4.6 21.3 0.34/0.63 40 80 665 V3 4.4 23.0 0.35/0.63 40 80 480 E3a 4.5 22.7 0.35/0.63 40 80 630 E3b 4.6 22.2 0.35/0.63 40 80 710 E3c 4.45 21.8 0.35/0.63 40 80 770 E3d 4.8 22.2 0.35/0.63 40 80 660 E3e 4.4 23.1 0.35/0.63 40 80 665 E3f 4.6 22.4 0.34/0.62 40 80 710 V4 5.0 19.2 0.34/0.62 40 80 675 E4a 5.2 19.3 0.34/0.62 40 80 1040 E4b 4.9 18.6 0.34/0.62 40 80 1160 E4c 4.9 19.5 0.34/0.62 40 80 1265 E4d 5.0 18.4 0.34/0.62 40 80 1140 E4e 4.9 19.3 0.34/0.62 40 80 830 E4f 5.1 18.2 0.34/0.62 40 80 880 V5 4.5 18.1 0.34/0.62 40 80 1070 E5a 4.6 18.4 0.34/0.62 40 80 1815 E5b 4.4 17.3 0.34/0.62 40 80 1320 E5c 4.4 18.7 0.34/0.62 40 80 1650 E5d 4.3 18.6 0.34/0.62 40 80 1295 E5e 4.7 18.4 0.34/0.62 40 80 1400 E5f 4.5 16.5 0.34/0.62 40 80 1980 E5g 4.4 18.8 0.34/0.63 40 80 1690 V6 4.5 21.9 0.35/0.63 40 80 630 E6a 4.4 22.4 0.35/0.63 40 80 765 E6b 4.4 22.9 0.35/0.63 40 80 720 E6c 4.3 23.1 0.35/0.63 40 80 990 E6d 4.5 22.1 0.35/0.63 40 80 790 E6e 4.6 22.5 0.35/0.63 40 80 835 E6f 4.3 21.5 0.35/0.63 40 80 745

TABLE 10 Structural formulae of the materials of the OLEDs used, if not already described before

PD1

SpMA1

SpMA2

ST2

LiQ

TE1

TE2

BCbz1

BCbz2

BCbz3

The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The solvents and reagents can be purchased, for example, from Sigma-ALDRICH or ABCR. The respective figures in square brackets or the numbers quoted for individual compounds relate to the CAS numbers of the compounds known from the literature.

To an initial charge of 1-chloro-8-bromodibenzofuran (100 g, 353.6 mmol) [CAS-2225909-61-3] and B-(9-phenyl-9H-carbazol-2-yl)boronic acid (106.6 g, 371.3 mmol) [1001911-63-2] in toluene (800 ml), 1,4-dioxane (800 ml) and water (400 ml) under inert atmosphere are added Na₂CO₃ (74.95 g, 0.71 mol) and tetrakis(triphenylphosphine)palladium(0) (4.09 g, 3.54 mmol), and the mixture is stirred under reflux for 16 h.

After cooling, the mixture is filtered with suction through a Celite-filled frit, and worked up by extraction with toluene and water. The aqueous phase is extracted twice with toluene (500 ml each time), and the combined organic phases are dried over Na₂SO₄. The solvent is removed on a rotary evaporator, and the crude product is converted to a slurry with ethanol (1200 ml) and stirred under reflux for 2 h. The solids are filtered off with suction, washed with ethanol and dried in a vacuum drying cabinet.

Yield: 138.5 g (312.2 mmol, 88%), 97% by ¹H NMR The following compounds can be prepared analogously: Purification can also be accomplished using column chromatography, or recrystallization or hot extraction using other standard solvents such as ethanol, butanol, acetone, ethyl acetate, acetonitrile, toluene, xylene, dichloromethane, methanol, tetrahydrofuran, n-butyl acetate, 1,4-dioxane, or recrystallization using high boilers such as dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.

Reactant 1 Reactant 2 Product Yield

63%

62%

71%

77%

56%

52%

68%

69%

67%

52%

68%

72%

80%

73%

66%

60%

To an initial charge of S1a (124.30 g, 280 mmol) and 4,4,5,5-tetramethyl-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,2-dioxaborolane (76.20 g, 300 mmol) in 1,4-dioxane (2000 ml) under inert atmosphere are added potassium acetate (82.33 g, 1.40 mol) and trans-dichlorobis(tricyclohexylphosphine)palladium(II) (6.21 g, 83.9 mmol), and the mixture is stirred under reflux for 32 h. After cooling, the solvent is removed by rotary evaporation on a rotary evaporator, the residue is worked up by extraction with toluene/water, and the organic phase is dried over Na₂SO₄. The crude product is extracted by stirring under reflux with ethanol (1100 ml), and the solids are filtered off with suction after cooling and washed with ethanol.

Yield: 113.5 g (212.5 mmol, 76%), 95% by ¹H NMR.

The following compounds can be prepared analogously: Purification can also be accomplished using column chromatography, or recrystallization or hot extraction using other standard solvents such as ethanol, butanol, acetone, ethyl acetate, acetonitrile, toluene, xylene, dichloromethane, methanol, tetrahydrofuran, n-butyl acetate, 1,4-dioxane, or recrystallization using high boilers such as dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.

Reactant 1 Product Yield

79%

70%

66%

67%

72%

64%

66%

78%

59%

71%

62%

67%

80%

82%

72%

76%

To an initial charge of 9-phenyl-3-[9-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-dibenzofuran-2-yl]-9H-carbazole (22.00 g, 41.1 mmol) [2239299-50-2], 2-chloro-4-{8-oxatricyclo[7.4.0.0²,7]trideca-1(13),2(7),3,5,9,11-hexaen-5-yl}-6-phenyl-1,3,5-triazine (14.70 g, 41.1 mmol) [CAS-2142681-84-1] in THE (650 ml) and water (250 ml) under inert atmosphere are added Na₂CO₃ (9.58 g, 90.4 mmol) and tetrakis(triphenylphosphine)palladium(0) (710 mg, 0.62 mmol), and the mixture is stirred under reflux for 16 h. After cooling, the mixture is worked up by extraction with toluene/water, the aqueous phase is extracted 3 times with toluene (250 ml each time), and the combined organic phases are dried over Na₂SO₄. The crude product is subjected to extraction with hot heptane/toluene twice, recrystallized from n-butyl acetate twice and finally sublimed under high vacuum.

Yield: 15.5 g (21.2 mmol, 52%); purity: >99.9% by HPLC

The following compounds can be prepared analogously: The catalyst system used here (palladium source and ligand) may also be Pd₂(dba)₃ with SPhos [657408-07-6] or bis(triphenylphosphine)palladium(II) chloride [13965-03-2]. Purification can also be accomplished using column chromatography, or recrystallization or hot extraction using other standard solvents such as ethanol, butanol, acetone, ethyl acetate, acetonitrile, toluene, xylene, dichloromethane, methanol, tetrahydrofuran, n-butyl acetate, 1,4-dioxane, or recrystallization using high boilers such as dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.

Reactant 1 Reactant 2 Product Yield

54%

46%

51%

57%

62%

60%

54%

44%

46%

44%

49%

38%

39%

55%

41%

53%

59%

56%

54%

45%

46%

58%

32%

38%

40%

To an initial charge of 9-[1,1′-biphenyl]-3-yl-3-bromo-9H-carbazole (59.88 g, 150.3 mmol) [CAS-1428551-28-3], 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indolo[3,2,1-jk]carbazole (51.1 g, 147.3 mmol) [CAS-1454807-26-1] in toluene (1200 ml), 1,4-dioxane (1200 ml) and water (600 ml) under inert atmosphere are added K₃PO₄ (95.7 g, 451 mmol), tri(ortho-tolyl)phosphine (2.33 g, 7.52 mmol) and Pd(OAc)₂ (840 mg, 3.76 mmol), and the mixture is stirred under reflux for 32 h. After cooling, the mixture is worked up by extraction with toluene/water, the aqueous phase is extracted 3 times with toluene (500 ml each time), and the combined organic phases are dried over Na₂SO₄. The crude product is first extracted by stirring in EtOH (1500 ml). The solids filtered off are subjected to extraction with hot heptane/toluene twice, recrystallized from DMAc twice and finally sublimed under high vacuum.

Yield: 40.5 g (72.5 mmol, 48%); purity: >99.9% by HPLC

The following compounds can be prepared analogously: The catalyst system (palladium source and ligand) used here may also be Pd₂(dba)₃ with SPhos [657408-07-6], or tetrakis(triphenylphosphine)palladium(0) or bis(triphenylphosphine)palladium(II) chloride [13965-03-2]. Purification can also be accomplished using column chromatography, or recrystallization or hot extraction using other standard solvents such as ethanol, butanol, acetone, ethyl acetate, acetonitrile, toluene, xylene, dichloromethane, methanol, tetrahydrofuran, n-butyl acetate, 1,4-dioxane, or recrystallization using high boilers such as dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide N-methylpyrrolidone etc.

Reactant 1 Reactant 2 Product Yield

47%

59%

64%

55%

50%

45%

58%

62%

38%

46%

40%

52%

41% 

1.-15. (canceled)
 16. An organic electroluminescent device comprising an anode, a cathode and at least one organic layer, containing at least one light-emitting layer, wherein the at least one light-emitting layer contains at least one compound of the formula (1) as host material 1 and at least one compound of the formula (2) as host material 2

where the symbols and indices used are as follows: X is the same or different at each instance and is CR0 or N, where at least one symbol X is N; X₁ is the same or different at each instance and is CH, CR or N, where not more than 3 symbols X₁ can be N; X₂ is the same or different at each instance and is CH, CR¹ or N, where not more than 2 symbols X₂ can be N; Y is the same or different at each instance and is selected from O or S; L and L₁ are the same or different at each instance and are a single bond or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms; R⁰ at each instance is independently H, D or an unsubstituted or partly or fully deuterated aromatic ring system having 6 to 18 carbon atoms; R and R# are the same or different at each instance and are selected from the group consisting of D, F, Cl, Br, I, CN, NO₂, C(═O)R², P(═O)(Ar₁)₂, P(Ar₁)₂, B(Ar₁)₂, Si(Ar₁)₃, Si(R²)₃, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, each of which may be substituted by one or more R² radicals, where one or more nonadjacent CH₂ groups may be replaced by R²C═CR², Si(R²)₂, C═O, C═S, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R² radicals, an aryloxy or heteroaryloxy group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals, or an aralkyl or heteroaralkyl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals; at the same time, it is possible for two substituents R bonded to the same carbon atom or to adjacent carbon atoms or for one substituent R together with Ar₃ to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R² radicals; R¹ is the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms; at the same time, it is possible for two substituents R¹ bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals; R² is the same or different at each instance and is selected from the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar₁)₂, NH₂, N(R³)₂, C(═O)Ar₁, C(═O)H, C(═O)R³, P(═O)(Ar₁)₂, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms, each of which may be substituted by one or more R³ radicals, where one or more nonadjacent CH₂ groups may be replaced by HC═CH, R³C═CR³, C≡C, Si(R³)₂, Ge(R³)₂, Sn(R³)₂, C═O, C═S, C═Se, C═NR³, P(═O)(R³), SO, SO₂, NH, NR³, O, S, CONH or CONR³ and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R³ radicals, an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R³ radicals, or a combination of these systems; where it is optionally possible for two or more adjacent substituents R² to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R³ radicals; R³ is the same or different at each instance and is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms in which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms; at the same time, it is possible for two or more adjacent R³ substituents together to form a mono- or polycyclic, aliphatic ring system; Ar₁ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more nonaromatic R³ radicals; at the same time, two Ar₁ radicals bonded to the same nitrogen atom, phosphorus atom or boron atom may also be bridged to one another by a single bond or a bridge selected from N(R³), C(R³)₂, O or S; Ar₂ at each instance is independently an aryl or heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals; Ar₃ at each instance is independently an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R² radicals; A at each instance is independently a group of the formula (3) or (4),

Ar at each instance is in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R# radicals; * indicates the binding site to the formula (2); a, b, c at each instance are each independently 0 or 1, where the sum total of the indices at each instance a+b+c is 1; o is 1, 2, 3 or 4; n, m and p at each instance are independently 1, 2 or 3; and q, r, s, t at each instance are each independently 0 or
 1. 17. The organic electroluminescent device according to claim 16, wherein L in host material 1 is selected from a bond or the linkers from the group of L-1 to L-33

where each W is independently O or S.
 18. The organic electroluminescent device according to claim 16, wherein host material 2 conforms to one of the formulae (2a), (2b) or (2c)

where the symbols and indices A, R¹, q, r and s used are as defined in claim
 16. 19. The organic electroluminescent device according to claim 16, wherein L₁ in host material 1 is a single bond.
 20. The organic electroluminescent device according to claim 16, wherein the device is an electroluminescent device selected from organic light-emitting transistors (OLETs), organic field quench devices (OFQDs), organic light-emitting electrochemical cells (OLECs, LECs, LEECs), organic laser diodes (O-lasers) and organic light-emitting diodes (OLEDs).
 21. The organic electroluminescent device according to claim 16, wherein the device comprises, in addition to the light-emitting layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), an electron injection layer (EIL) and/or a hole blocker layer (HBL).
 22. The organic electroluminescent device according to claim 16, wherein the light-emitting layer, as well as the at least one host material 1 and the at least one host material 2, contains at least one phosphorescent emitter.
 23. The organic electroluminescent device according to claim 22, wherein the phosphorescent emitter conforms to the formula (III)

where the symbols and indices for this formula (III) are defined as follows: n+m is 3, n is 1 or 2, m is 2 or 1, X is N or CR, R is H, D or a branched or linear alkyl group or a partly or fully deuterated, branched or linear alkyl group.
 24. A process for producing the device according to claim 16 comprising applying the light-emitting layer by gas phase deposition or from solution.
 25. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are deposited from the gas phase successively or simultaneously from at least two material sources, optionally with the at least one phosphorescent emitter, and form the light-emitting layer.
 26. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are deposited from the gas phase as a mixture, successively or simultaneously with the at least one phosphorescent emitter, and form the light-emitting layer.
 27. The process according to claim 24, wherein the at least one compound of the formula (1) and the at least one compound of the formula (2) are applied from a solution together with the at least one phosphorescent emitter in order to form the light-emitting layer.
 28. A mixture comprising at least one compound of the formula (1) as host material 1 and at least one compound of the formula (2) as host material 2

where the symbols and indices used are as follows: X is the same or different at each instance and is CR⁰ or N, where at least one symbol X is N; X₁ is the same or different at each instance and is CH, CR or N, where not more than 3 symbols X₁ can be N; X₂ is the same or different at each instance and is CH, CR¹ or N, where not more than 2 symbols X₂ can be N; Y is the same or different at each instance and is selected from O or S; L and L₁ are the same or different at each instance and are a single bond or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms; R⁰ at each instance is independently H, D or an unsubstituted or partly or fully deuterated aromatic ring system having 6 to 18 carbon atoms; R and R# are the same or different at each instance and are selected from the group consisting of D, F, Cl, Br, I, CN, NO₂, C(═O)R², P(═O)(Ar₁)₂, P(Ar₁)₂, B(Ar₁)₂, Si(Ar₁)₃, Si(R²)₃, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, each of which may be substituted by one or more R² radicals, where one or more nonadjacent CH₂ groups may be replaced by R²C═CR², Si(R²)₂, C═O, C═S, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system which has 5 to 40 aromatic ring atoms and may be substituted in each case by one or more R² radicals, an aryloxy or heteroaryloxy group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals, or an aralkyl or heteroaralkyl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals; at the same time, it is possible for two substituents R bonded to the same carbon atom or to adjacent carbon atoms or for one substituent R together with Ar₃ to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R² radicals; R¹ is the same or different at each instance and is selected from the group consisting of CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 20 carbon atoms, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 aromatic ring atoms, or an aralkyl or heteroaralkyl group having 5 to 40 aromatic ring atoms; at the same time, it is possible for two substituents R¹ bonded to the same carbon atom or to adjacent carbon atoms to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system that may be substituted by one or more R² radicals; R² is the same or different at each instance and is selected from the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar₁)₂, NH₂, N(R³)₂, C(═O)Ar₁, C(═O)H, C(═O)R³, P(═O)(Ar₁)₂, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atoms, each of which may be substituted by one or more R³ radicals, where one or more nonadjacent CH₂ groups may be replaced by HC═CH, R³C═CR³, C≡C, Si(R³)₂, Ge(R³)₂, Sn(R³)₂, C═O, C═S, C═Se, C═NR³, P(═O)(R³), SO, SO₂, NH, NR³, O, S, CONH or CONR³ and where one or more hydrogen atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R³ radicals, an aryloxy or heteroaryloxy group which has 5 to 60 aromatic ring atoms and may be substituted by one or more R³ radicals, or a combination of these systems; where it is optionally possible for two or more adjacent substituents R² to form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R³ radicals; R³ is the same or different at each instance and is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms in which one or more hydrogen atoms may be replaced by D, F, Cl, Br, I or CN and which may be substituted by one or more alkyl groups each having 1 to 4 carbon atoms; at the same time, it is possible for two or more adjacent R³ substituents together to form a mono- or polycyclic, aliphatic ring system; Ar₁ is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 30 aromatic ring atoms and may be substituted by one or more nonaromatic R³ radicals; at the same time, two Ar₁ radicals bonded to the same nitrogen atom, phosphorus atom or boron atom may also be bridged to one another by a single bond or a bridge selected from N(R³), C(R³)₂, O and S; Ar₂ at each instance is independently an aryl or heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R² radicals; Ar₃ at each instance is independently an aromatic ring system having 6 to 40 aromatic ring atoms or a heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more R² radicals; A at each instance is independently a group of the formula (3) or (4),

Ar at each instance is in each case independently an aryl group which has 6 to 40 aromatic ring atoms and may be substituted by one or more R# radicals, or a heteroaryl group which has 5 to 40 aromatic ring atoms and may be substituted by one or more R# radicals; * indicates the binding site to the formula (2); a, b, c at each instance are each independently 0 or 1, where the sum total of the indices at each instance a+b+c is 1; o is 1, 2, 3 or 4; n, m and p at each instance are independently 1, 2 or 3; and q, r, s, t at each instance are each independently 0 or
 1. 29. The mixture according to claim 28, wherein the mixture consists of at least one compound of the formula (1), at least one compound of the formula (2) and a phosphorescent emitter.
 30. A formulation comprising the mixture according to claim 28 and at least one solvent. 